Image graphic adhesive system and method for using same

ABSTRACT

An adhesively mountable image using a reusable adhesive surface is provided. The image carrier is removable from the adhesive carrier, and a subsequent image carrier may be releasably bound to the same adhesive carrier. Kits for this system are also provided.

FIELD OF INVENTION

[0001] This invention relates to combined adhesive/substrate systems forplacement and removal of image graphics.

BACKGROUND OF INVENTION

[0002] Image graphics are omnipresent in modem life. Images and datathat warn, educate, entertain, advertise, etc. are applied on a varietyof interior and exterior, vertical and horizontal surfaces. Nonlimitingexamples of image graphics range from posters that advertise the arrivalof a new movie to warning signs near the edges of stairways.

[0003] Readily replaceable image graphics are needed for those occasionswhen the length of time the graphic needs to remain at the intendedlocation is limited to a short duration, often with a replacement imagegraphic substituting for the image graphic to be removed. An example ofan expected replacement image graphic is the movie poster identifiedabove.

[0004] Readily replaceable image graphics require both the “stayingpower” when placed on the horizontal or vertical surface and the“leaving ease” when the image graphic is to be removed.

[0005] Among different kinds of readily replaceable image graphics arefilms that have an image on one major surface and a field of adhesive onthe opposing major surface. Again, movie posters and other bills areoften adhered to a surface. If the adhesive is pressure sensitive andcapable of being readily removed without leaving adhesive residue, thenthe poster can be posted and has staying power but is removed with ease.

[0006] While there are numerous methods of mounting image graphic filmsto a substrate, two methods that represent the present state-of-the-artare: Pressure Sensitive Adhesive (PSA) coated image-bearing substratesand mechanically fastened graphics. PSA coated substrates typicallyconsist of a PSA coated onto a polymer film such as plasticizedpolyvinyl chloride (PVC) or high quality paper stock, which are suppliedon a siliconized release paper to protect the PSA.

[0007] Mechanically fastened graphics can take many forms, examples ofwhich maybe printed paper stock that is simple stapled to a desiredsubstrate, printed cardboard or rigid polymer sheeting such asPlexiglas™ which can be mounted in position using nail, staples, clipsor other methods, or even a PSA coated graphic that can be mounted on arigid carrier such as cardboard and similarly mounted. Such graphics canalso be mounted using magnets or small pieces of hook and loop fasteneras described in U.S. Pat. No. 4,999,937 (Bechtold). Other mechanicalfasteners are disclosed in U.S. Pat. Nos. 5,196,266 and 5,316,849 (bothLu et al.). Alternatively, the hook and loop construction can reside onan opposing major surface of a film that can also be printed ondirectly, as described in PCT International Patent Publication WOUS98/39759 (Loncar).

[0008] Additionally, four types of systems bear special mention.

[0009] First, the manufacture of double-sided sheets frequently employ arelease liner spirally wound with the sheet itself. To the extent thatthe liner has images or printed information, that liner is interactingwith an adhesive but only for the duration of storage until use. Oncethe sheet is placed in use, the printed release liner is discarded. PCTPublication WO 97/07492 discloses a method of securing a picture on amovable picture carrier using a fastening means comprising adouble-sided carrier with differing amounts of adhesion on each of thetwo sides. This publication uses double-sided sheets in key perimeterlocations on picture to secure the picture to the carrier.

[0010] Second, 3M Post-It™ Memoboard #558 (Minnesota Mining andManufacturing Company (“3M”) of St. Paul, Minn., USA) provides asubstrate having an exposed major surface of “repositionable” adhesiveupon which individual pieces of paper or film as memos or notes can beadhered. The repositionability of notes on the major surface means thatthe adhesive is designed to have a low and limited amount of holdingpower.

[0011] Further, as the exposed major surface of adhesive becomescontaminated with dirt, oils etc., the adhesive can not be cleaned torestore its original holding power. In contrast, a pressure-sensitivedisplay board is disclosed in U.S. Pat. No. 3,952,133 (Amos et al.),where a bulletin board, display panel, or other posting device has apressure-sensitive adhesive surface on a thick resilient backing withthe pressure sensitive adhesive being preferably a water-washable tackyelastomer. However, this display board is intended to permit adhesion ofall types of materials including pens, keys, paper, small notebooks, andother disparate items (both light and heavy in mass). Thus, almost anyitem could conceivably adhere indiscriminately to the pressure-sensitiveadhesive surface.

[0012] Third, cling vinyl graphics bear special mention. The substrateto which cling vinyl image graphics bond is limited in adhesion toextremely smooth surfaces such as glass, which makes a bond that hasvery low adhesive holding power. In addition, while not a PSA, the clingvinyl is generally supplied on a release liner in order to preventblocking (material sticking to itself), and sticking to smooth surfacessuch as metal printer equipment.

[0013] Fourth, U.S. Pat. No. 5,462,782 (Su et al.) discloses a targetadhesive layer that can only be bonded to the same limited number ofsurfaces that are available to cling vinyl, where such surfaces haveexposed adhesive having a tack that attracts dirt and can not be washedto restore the original adhesion of the adhesive. In another system, PCTPublication WO 95/06692 (Fuji) discloses a self adhesive film, thatadheres to itself but not to other materials.

[0014] Image graphics using pressure sensitive adhesive surfaces, whileextremely versatile, can encounter a number of limitations. First isthat the inherent tackiness of the adhesive causes problems in applyingthe graphic smoothly and evenly to the surface. If the graphic ismisaligned or wrinkled during application, the graphic must be removedand reapplied. In the worst case, the graphic can be damaged removingit, which means the graphic needs to be replaced with a new graphic, aconsiderable expense. Improvements such as contained in Controltac™branded films sold by 3M have special adhesives to limit the initialadhesion, and thus allow limited repositionability. Repositionability ofan adhesive is also described in U.S. Pat. No. 5,296,277 (Wilson etal.). Moreover, a multi-cycle refastenable contact responsive non-tackyfastener system is disclosed in PCT Publication WO 94/21742 (Kobe etal.).

[0015] While the use of special adhesive formulations definitelyprovides assistance in the initial placement of the graphics, theseimproved adhesives are not designed specifically for problems such aswrinkles that show up after the major portion of a graphic has beenapplied.

[0016] To assist in the removal of wrinkles, the adhesive can be furthermodified to limit tack, either chemically such as altering the glasstransition temperature (Tg) of the adhesive composition, or physically,such as pattern coating or using microspheres. One approach taken usingphysical modification is disclosed in PCT Patent Publication WO 98/29516(Sher et al.). However, this approach ends up causing a secondlimitation in image graphics using pressure sensitive adhesives: theadhesive must bond acceptably to numerous substrates for the intendedapplication.

[0017] In most cases, commercially available pressure sensitiveadhesives will bond acceptably to some substrates but have high adhesionto others. Moreover, when an adhesive is formulated to be removable, thesituation worsens, because the adhesive can have three possible levelsof adhesion: too high, too low or acceptable. Therefore, pressuresensitive adhesives are often formulated with a compromise inperformance that all too often is not optimum for a particularapplication.

[0018] For the situation when graphics are applied to a variety ofsubstrates, a variety of films with different pressure sensitiveadhesive formulations may be needed to complete the job. This results inmore logistical problems for the customer.

[0019] Another issue facing films that have an image on one majorsurface and a field of adhesive on the opposing major surface is thecare during storage and placement so as not to contaminate the adhesivewith dirt or other effects that diminish the intended adhesiveness. Forthat reason, a second film or paper is laminated to the adhesive surfaceand serves as a protective liner.

SUMMARY OF INVENTION

[0020] The present invention provides a method of displaying an imageusing a reusable adhesive surface. In this method, a flexible adhesivecarrier is provided having first and second major surfaces, each surfacebeing substantially covered by an adhesive. The first adhesive surfaceis engineered to bond the adhesive carrier to a substrate. The secondadhesive surface is engineered to releasably secure an image carrier tothe adhesive carrier. This adhesive carrier is bonded to a substrate atthe first surface.

[0021] A flexible image carrier is also provided having first and secondmajor surfaces, the first surface being imageable and the second surfacebeing adapted to contact the releasably securing adhesive surface of theadhesive carrier. The image carrier is not adapted to adhere to thesubstrate. In the method of the present invention, the image carrier isimaged on the first surface, and removably adhered to the adhesivecarrier by contacting the second surface of the image carrier with thesecond surface of the adhesive carrier. The image carrier resides on theadhesive carrier for a predetermined period of time. The image carrierand the adhesive carrier are substantially coextensive in size.

[0022] Additional methods provided herein include methods for displayingmultiple images using a reusable adhesive surface, and such methodswhere the image is applied to a transparent substrate for viewingthrough the substrate. Additionally, kits of materials specially adaptedfor use with the described methods are provided.

BRIEF DESCRIPTION OF DRAWINGS

[0023]FIG. 1 is a cross-sectional view of an embodiment of the imagegraphic adhesive system of the present invention.

DETAILED DESCRIPTION

[0024] The present invention provides an adhesively mountable imagegraphic system wherein the adhesive is provided as a separate componentfrom the image carrier. The separation of these components (as comparedto prior art constructions that required the image carrier to itself becoated with an adhesive) surprisingly provides a more versatile; easierto manufacture, image and apply; and potentially much less expensiveadhesively mountable image graphic system.

[0025] As noted above, the image carrier is flexible, and has a firstmajor surface that is imageable and a second major surface that isadapted to contact the adhesive carrier, but will not adhere to thesubstrate. This is in contrast with the prior art adhesively mountableimage graphic, which contains a layer of adhesive with a release linercovering the adhesive to prevent unwanted adhesion during the handlingprocess. In the prior art system, any errors in imaging resulted inruining a costly multilayer construction. The present imaging materialis capable of being much lower in cost than the corresponding prior artconstruction, and results in much less material loss in case of error.Cost savings are particularly realized in the present system whenmultiple image carriers are used sequentially on the same adhesivecarrier. Each image carrier that is displayed on an adhesive carrierafter the first image carrier provides a savings of the adhesivematerial and corresponding release liner that would otherwise be presentusing prior art systems. A preferred system provides an adhesive carrierthat is capable of being used with about 10-50 image carriers in asequential manner. The more often an adhesive carrier is reused, thegreater the savings provided by the present system. A particularlypreferred system provides an adhesive carrier that may reside on thesubstrate for a period of 1-2 years, with a new image optionally appliedevery 1-2 weeks. Additionally, because no adhesive or liner layers needbe present, the present image carrier material may be much easier tohandle than the corresponding prior art construction.

[0026] In preferred embodiments, either or both the image carrier andthe adhesive carrier may be reused—the image carrier at another location(or the same location at a later date), and the adhesive carrier withanother image carrier. This ability to reuse one or both carriersprovides a significant advantage to the system of the present invention.

[0027] Because both the image carriers and the adhesive carriers areflexible, the present system is easy to handle, transport and store. Theadhesively mountable image graphic may optionally be applied to asubstrate having a non-planar geometry, such as a curved surface.

[0028] In one embodiment, the present invention provides the ability toprint images on image carriers that have not been coated with anadhesive. Such image carriers may be substantially thinner thanadhesive-coated image carriers, because they do not have a release linerprotecting the adhesive. This difference in structure may make itpossible for a greater variety of printing methods to be used withadhesively mountable image graphic materials, including those previouslyunavailable due to an inability to print on a medium that wasadhesive-backed. The prior art method of providing an adhesivelyattachable image graphic required the presence on an adhesive on theback of an image graphic. This in turn requires the use of a liner,which itself increased the cost of the image graphic. More importantly,the liner to be used on such an image graphic further had to havespecial, usually costly characteristics to permit the liner to gothrough printing equipment. Those special requirements are avoided byimage graphic marking system of the present invention.

[0029] The present invention additionally provides a significant benefitin allowing the user to store and use an image carrier that is notadhesive-backed and not liner-backed. Because the image carrier is lessexpensive by virtue of not containing as many materials, the expenses ofinventory and shipment are reduced. Additionally, the risk of damage ofthe image caused by contact of the image with an adhesive or itscomponents, or of ineffectiveness of the adhesive due to retentionbeyond its effective shelf life is also reduced or eliminated.

[0030] Optionally, an image may be provided on both sides of the imagecarrier. Alternatively, an image also may be provided on the adhesivecarrier before application of the adhesive that will contact theintended substrate. This construction allows provision of an image thatremains on the substrate (viewable through a transparent substrate orthrough the image carrier if the image carrier is transparent ortranslucent) as long as the adhesive carrier is in place, with achangeable image on the opposite side of the construction.

[0031] A preferred embodiment of the present invention is a method ofdisplaying multiple images at the same location in a serial manner usinga reusable adhesive surface, comprising the steps of:

[0032] (a) providing a flexible adhesive carrier having first and secondmajor surfaces, each surface being substantially covered by an adhesive,the first adhesive surface engineered to bond the adhesive carrier to asubstrate and the second adhesive surface engineered to releasablysecure an image carrier to the adhesive carrier;

[0033] (b) bonding the adhesive carrier to a substrate at the firstsurface;

[0034] (c) providing a first flexible image carrier having first andsecond major surfaces, the first surface being imageable and the secondsurface being adapted to contact the releasably securing adhesivesurface of the adhesive carrier, wherein the first image carrier is notadapted to adhere to the substrate;

[0035] (d) imaging the first image carrier on the first surface;

[0036] (e) removably adhering the first image carrier to the adhesivecarrier by contacting the second surface of the first image carrier withthe second surface of the adhesive carrier, and allowing said firstimage carrier to reside on said adhesive carrier for a predeterminedperiod of time;

[0037] (f) providing a second flexible image carrier having first andsecond major surfaces, the first surface being imageable and the secondsurface being adapted to contact the releasably securing adhesivesurface of the adhesive carrier, wherein the second image carrier is notadapted to adhere to the substrate;

[0038] (g) imaging the second image carrier on the first surface;

[0039] (h) removing the first image carrier from the adhesive carrier;and

[0040] (i) removably adhering the second image carrier to the adhesivecarrier by contacting the second surface of the second image carrierwith the second surface of the adhesive carrier, and allowing saidsecond image carrier to reside on said adhesive carrier for apredetermined period of time; wherein the image carriers and theadhesive carrier are substantially coextensive in size.

[0041] It should be noted that any of the steps in the methods describedherein may be taken in any order, provided that preparation stepsessential to another step be undertaken first. For example, steps (c)and (f) may be carried out at substantially the same time, since theyare both image carrier manufacturing steps. Likewise, steps (d) and (g)may be carried out at substantially the same time, since they are bothimaging steps and may logically be done at the same time even though thesecond image carrier would have to be stored for some time before use.Since the image carrier is flexible, it could optionally be stored inrolled-up fashion. Obviously, step (g) could not be done before step(f), since (f) is a preparation step required to provide a material usedin step (g). It is particularly preferred to perform steps (c) and (d)before step (b), since it is desirable to have the first image carrieralready on hand and ready to apply once the adhesive carrier is adheredto the substrate.

[0042] In a particularly preferred embodiment, the first image carrieris provided ready for imaging already mounted on a reusable adhesive.Subsequent image carriers may replace the first image carrier. Thisembodiment allows efficient delivery of the adhesive carrier to thesubstrate, while still providing the benefit of a reusable adhesive inplace on a substrate. In this embodiment, a method of displaying animage using a reusable adhesive surface is provided, comprising thesteps of:

[0043] (a) providing an adhesively mountable image graphic compositehaving a reusable adhesive surface, comprising:

[0044] (i) a flexible adhesive carrier having first and second majorsurfaces, each surface being substantially covered by an adhesive, thefirst adhesive surface engineered to bond the adhesive carrier to asubstrate and the second adhesive surface engineered to releasablysecure an image carrier to the adhesive carrier; and

[0045] (ii) a flexible image carrier having first and second majorsurfaces, the first surface being imageable and the second surface beingin releasable contact with the releasably securing adhesive surface ofthe adhesive carrier;

[0046] wherein the image carrier and the adhesive carrier aresubstantially coextensive in size;

[0047] (b) imaging the image carrier on the first surface of the imagecarrier; and

[0048] (c) bonding the adhesive carrier to a substrate at the firstsurface of the adhesive carrier.

[0049] Alternatively, the image carrier may first be imaged, and thensecured to the adhesive carrier. This pre-imaged composite may then beprovided to the applicator for bonding to the intended substrate.

[0050] The adhesive carrier may be provided with a separate releaseliner covering both the first adhesive and the second adhesive surfaces.Alternatively, a single release liner could be used, with each carrierrolled on itself, thereby using both sides of the release liner with thesingle adhesive carrier. The liner may be treated differently on eachside to provide appropriate release characteristics such that the firstadhesive surface is exposed for application to the substrate before thesecond adhesive surface is exposed for securing the image carrier. Inanother alternative delivery system, the adhesive carrier may beprovided to the applicator in a pad of carriers, having a single releaseliner located between two adhesive carriers.

[0051] In another embodiment of the present invention, a method isprovided for displaying an image through a substrate (such as a windowand the like) using a reusable adhesive surface. This method comprisesthe steps of:

[0052] (a) providing a transparent or translucent, flexible adhesivecarrier having first and second major surfaces, each surface beingsubstantially covered by an adhesive, the first adhesive surfaceengineered to bond the adhesive carrier to a substrate and the secondadhesive surface engineered to releasably secure an image carrier to theadhesive carrier;

[0053] (b) bonding the adhesive carrier to a transparent or translucentsubstrate at the first surface;

[0054] (c) providing a flexible image carrier having first and secondmajor surfaces, the first surface being imageable and further beingadapted to contact the releasably securing adhesive surface of theadhesive carrier, wherein the image carrier is not adapted to adhere tothe substrate;

[0055] (d) imaging the image carrier on the first surface such that theimage does not transfer to the adhesive carrier upon removal from theadhesive carrier;

[0056] (e) removably adhering the image carrier to the adhesive carrierby contacting the first surface of the image carrier with the secondsurface of the adhesive carrier, and allowing said image carrier toreside on said adhesive carrier for a predetermined period of time;

[0057] wherein the image carrier and the adhesive carrier aresubstantially coextensive in size.

[0058] Similarly to the methods described above, this method mayadditionally be used with a plurality of image carriers in a serialmanner.

[0059] The image is provided in a manner such that the image does nottransfer to the adhesive carrier upon removal from the adhesive carrier.A non-transferring image may be provided by using high quality inks orimaging materials and/or using a protective overlaminate material.

[0060] Images may optionally be provided on both sides of the imagecarrier, to provide two-way image display from the same construction.

[0061] In a particularly preferred embodiment, the adhesive carrier isremovable from the substrate without tearing of the adhesive carrier.This allows for easy removal of the adhesive carrier from the substrate,after which the substrate may be restored to its original condition orprepared with a new adhesive carrier for a new cycle of image displays.

[0062] In another particularly preferred embodiment, the image carriermay be removed and reapplied to the adhesive carrier without distortionor damage to the image. This embodiment provides specifically for reuseof the image carrier at another time or location.

[0063] In a particularly preferred embodiment, the adhesive on thesecond adhesive surface is washable. For purposes of the presentinvention, a “washable” adhesive is an adhesive that can be treated byan appropriate cleaning solution (such as water or soap and water) toremove adhesively detrimental materials, thereby at least partiallyrefreshing the adhesion of a used surface. After a number of uses, theadhesive may become dirty or otherwise detackified. Washing of washableadhesives removes materials that detract from the adhesion performanceof the surface, and refreshes the surface for additional uses foradhesion of image carriers to the substrate.

[0064] In a preferred embodiment of the present invention, the substrateis a front panel of a backlit light display. Thus, the present inventionprovides a system for displaying an image using a reusable adhesiveunder the demanding conditions of images that are illuminated frombehind the image and through the adhesive. Examples of such displaysinclude windows and other transparent or translucent substrates thathave a light source behind them. More preferably, the display is a lightbox display, such as are popularly used for advertising purposes inmalls and airport terminals. A preferred embodiment of the presentinvention provides the adhesive carrier and the image carrier astransparent materials. This embodiment is particularly suited inwindow-type displays, or in light box displays where a separate materialwill be used to diffuse light. Alternatively, the adhesive carrier andthe image carrier may be individually selected to be transparent ortranslucent, such that they are suitable for use for attachment to thefront panel of a backlit light display. If both are transparent, aseparate light diffuser may be provided for use in the light box. If oneor both are translucent, the adhesive carrier and/or the image carriermay themselves act as the light diffuser, eliminating the need to add anadditional diffuser film or material.

[0065] Certain sizes of carriers are particularly preferred for use inthe present invention. Thus, the image carrier and the adhesive carrierare preferably ⅛-3 meters wide by ⅛-3 meters long, more preferably ½-3meters wide by ½-3 meters long and yet more preferably 1-3 meters wideby 1-3 meters long.

[0066] Of particular advantage is the ability to provide a readilychangeable high quality image graphic. Thus, the image carrier ispreferably imaged using a method selected from the group consisting ofthermal transfer of colorant, inkjet printing, screen printing, offsetprinting, flexographic printing, laser printing, electrophotographicprinting, electrostatic transfer printing, and combinations thereof.Preferred images are provided by high quality, four color, highresolution imaging techniques. Preferably, the image has a resolution of200 dpi or greater, more preferably 300 dpi or greater, and mostpreferably 500 dpi or greater.

[0067] An embodiment of the present invention that is particularlypreferred is the use in multiple face, multiple component, rotatingbillboard systems. The billboard is constructed using, for example,multiple panels that align to form a flat image surface. Each panel isactually one face on, for example, a three face elongated component.Upon rotation of the components of a three-face billboard, the secondface of each component is aligned to form a second flat image. Likewise,another rotation of the components aligns the third face of thecomponents to form a third flat image. A final rotation returns thefirst image to the view of the observer.

[0068] The adhesive carrier has adhesive coated over the entirety ofboth major surfaces, in order to assure maximum bonding to the substratefor one major surface and releasably securing of the other major surfacefor the image carrier. In the situation where the carrier is itselfadhesive, no additional adhesive material need be coated on the surface.The surface, therefore, can be stated to be covered by an adhesive,since the entire surface of the adhesive carrier displays adhesiveproperties.

[0069] In one embodiment of the present invention, the adhesive surfaceon the adhesive carrier may be selected to be highly versatile withrespect to its ability to adhere a variety of image carriers throughrepetitious installations without diminishment of the assured usage forthe desired duration and environment.

[0070] In another embodiment of the present invention, the imagecarrier's adhesive-contacting surface and the image carrier-contactingsurface of the adhesive carrier may be selected to be compatible inorder to maximize assured usage for specific durations and in specificenvironments.

[0071] In yet another embodiment of the present invention, the adhesivecarrier may be selected such that it discriminately adheres to onlycertain image carrier materials, and do not adhere to other imagecarrier materials.

[0072] Another advantage of the invention is the ease of singleinstallation of the adhesive carrier on the substrate and the ease ofmultiple installations of the image carrier on the adhesive carrier andremoval therefrom without residue of adhesive, if the appropriate imagecarrier has been used with the appropriate adhesive carrier. In otherwords, it is possible to engineer the image graphic adhesive system ofthe present invention to discriminate among various compositions ofimage carriers such that only certain image carriers adhere at all tothe releasable securing adhesive surface of the adhesive carrier.Moreover, it is possible in such engineered interaction of the imagecarrier and the adhesive carrier, that incorrect image carriers will notadhere at all to the adhesive carrier in the one extreme or incorrectimage carriers will adhere permanently to the adhesive carrier in theother extreme. At either extreme, attempts to use the adhesive carrierto adhere incorrect image carriers will cause an inappropriate usage tobe recognized by the owner of the substrate. For example, mediacompanies lease surface space for advertising or sales promotion thatcan use the image graphic adhesive system of the present invention toprovide appropriate image carriers or none at all.

[0073] Further features and advantages of the invention will becomeevident in the following discussion of embodiments of the invention, inrelation to the drawing.

[0074] Image Graphic Adhesive System

[0075]FIG. 1 shows elements of an image graphic system that is common tovarious embodiments of the present invention. Image graphic system 10,comprises an adhesive carrier 12 durably bonded to substrate 14 ofindeterminate thickness, upon which adhesive carrier 12, a image carrier16 is releasably adhered.

[0076] Adhesive carrier 12 releasably secures image carrier 16 tosubstrate 14. Adhesive carrier 12 can comprise an adhesive surface 22that durably bonds adhesive carrier 12 to substrate 14; a transparent,translucent, or opaque adhesive intergrity layer 24 that providesdurable integrity of adhesive carrier 12 on substrate 14; and anadhesive surface 26 that releasably secures image carrier 16 in a mannerthat image carrier 16 can be repositioned or removed. Alternatively,adhesive carrier 12 can comprise only two adhesive surfaces 22 and 26,omitting adhesive integrity layer 24 if one or both of the adhesiveshave sufficient integrity for the surface area of substrate 14 to becovered by image carrier 16. Alternatively, adhesive carrier 12 cancomprise only one adhesive formulation with two surfaces 22 and 26, ifthe adhesive performance allows both durable bonding to the substrate 14and repositionable adhesion of image carrier 16 thereto.

[0077] Image carrier 16 can comprise an adhesive-contacting surface 32that removably adheres to adhesive surface 26; a transparent,translucent, or opaque integrity layer 34 that provides durableintegrity of image carrier 16 on adhesive carrier 12; and an imageablesurface 36 that permits printing of an image graphic (collectively shownas 40) thereon. Alternatively, image carrier 16 can comprise onlyadhesive contacting surface 32 and imageable surface 36, omitting aseparate integrity layer 34 if one or both of the adhesive-contactingsurface 32 or imageable surface 36 have sufficient integrity for thesurface area of substrate 14 to be covered by image carrier 16.Alternatively, image carrier 16 can comprise only one integralformulation that provides both an acceptable adhesive-contacting surface32 and an imageable surface 36, if such formulation is available to thesatisfaction of those skilled in the art.

[0078] The embodiment shown in FIG. 1 differs from conventional imagegraphics films that have an adhesive surface opposing an image, becausethe adhesive surface 26 is a part of the adhesive carrier 12 rather thanbeing borne on image carrier 16. Moreover, the image graphic adhesivesystem of the present invention interposes a new adhesive interfacebetween adhesive surface 26 and adhesive-contacting surface 32 that canbe specifically engineered for uses of specific duration andenvironment. The image graphic system 10 therefore is a combination ofadhesive carrier 12 and image carrier 16 with the interface betweenadhesive surface 26 and adhesive-contacting surface 32 being vital tothe performance of the system 10 for multiple placement and release.Moreover, the interface between adhesive surface 22 and substrate 14 isalso significant to assure controlled but durably secure attachment ofadhesive carrier 12 to substrate 14, such that when image carrier 16 isremoved, adhesive carrier 12 remains bonded to substrate 14.

[0079] A key element of the difference between the adhesion to thesubstrate and the adhesion to the image graphic is that the adhesion tothe substrate 14 be greater than the adhesion to the image carrier 16.The discussion of differential peel adhesion below applies to allpreferred embodiments of the present invention that exhibit thisdifferential peel adhesion, not only to the embodiment illustrated inthe figure.

[0080] One method to engineer the interface of image carrier 16 andadhesive carrier 12 and the interface of adhesive carrier 12 andsubstrate 14 is to compare the 90° peel adhesion for each interfaceusing a standard 90° peel adhesion taught by DIN EN 28510 (part 1=90°,part 2=180°), utilizing the peel speed, substrate, and dwell timesindicated herein.

[0081] In cases where a siliconized image carrier was used, a 180° peeltest was employed as described in the Examples below. This test wasemployed because the 90° peel on these systems was very low and almostunmeasurable. 180° peel—most common for siliconized surfaces—gives ahigher more measurable number. It is preferred that the peel at anyangle between 20° and 180° gives the right relationship of surfacereleases, because preferably a user of the image graphic system of thepresent invention may peel the image carrier 16 from adhesive carrier 12at any of those angles between 20° and 180°.

[0082] One characteristic of the image graphic adhesive system of thepresent invention is that the peel adhesion for the interface betweenadhesive carrier 12 and image carrier 16 is less than the peel adhesionfor the interface between adhesive carrier 12 and substrate 14 after adwell time of about 24 hours. Preferably, the 20°-180° peel adhesion forthe interface between adhesive carrier 12 and image carrier 16 rangesfrom about 0.1 percent, to about 90 percent, percent of the 20°-180°peel adhesion for the interface between adhesive carrier 12 andsubstrate 14 after a dwell time of about 24 hours. Toward the 0.1% endof the range identified. above, one could have a high strengthnon-removable surface bond in combination with a siliconized imagecarrier. Toward the 90% end of the range identified above, one couldhave a releasable adhesive bond to substrate 14 in combination with arelatively strong adhesive bond between the image carrier 16 andadhesive carrier 12.

[0083] In other words, with a baseline of peel adhesion between adhesivecarrier 12 and substrate 14 considered as durably secure, the fractionof that peel adhesion between adhesive carrier 12 and image carrier 16permit releasable removal of image carrier 16 from adhesive carrier 12.

[0084] Preferably, the percentage ranges from about 1 to about 80 inorder to provide ease of removal but sufficient adhesion during use whenmeasured after a 24 hour dwell time.

[0085] Adhesion at interfaces changes over time. Therefore at about 14days of dwell time, the percentage ranges from about 0.1 to about 90 inorder to provide predictable performance at the respective interfaces,based on choices of adhesives and how such adhesives interact with thesurfaces such adhesive contact over time.

[0086] The differential interfacial adhesions for both 24 hour dwelltime and 14 day dwell time are expressed as percentages because theactual values of peel adhesion can vary according to the varieties ofsubstrates, adhesive carriers, and image carriers. However, one skilledin the art can adapt the selection of materials for adhesive carriersand image carriers based upon the type of substrate and the amount ofduration and environmental conditions that affect both the securement ofadhesive carrier 12 to substrate 14 and the releasable adhesion of imagecarrier 16 to adhesive carrier 12.

[0087] Additionally, the selection of materials for adhesive carriersand image carriers to establish differential interfacial adhesions canbe based on a choice of the bond peel adhesion or the securing peeladhesion. One skilled in the art, knowing the desired range offractional peel adhesion, can begin with the peel adhesion of thereleasable securing adhesive surface 26 of the adhesive carrier 12 orthe peel adhesion of the securing surface 22, in order to engineer animage graphic adhesive system suitable for specific use. Thus, the“baseline” of 20°-180° peel adhesion can begin from either adhesivesurface 22 or 26.

[0088] The adhesive-contacting surface 32 of image carrier 16 is thesurface designed in system 10 to releasably adhere to adhesive surface26. Depending on the qualities of the adhesive chosen for adhesivesurface 26, the adhesive-contacting surface 32 can be a variety ofmaterials, depending on desired usage parameters of duration andenvironment. For each variety of adhesive surface 26, specificadhesive-contacting surfaces 32 of image carrier 16 are preferred.

[0089] For example, one embodiment for adhesive surface 26 can bedescribed as adhesive that is not tacky to contact with most materialsbut is capable of releasably securing to adhesive-contacting surface 32of image carrier 16 at the image interface. In other words, adhesivesurface 26 is discriminately adhesive and otherwise has little or notack for adhesion of other materials that do not meet the qualificationsof adhesive-contacting surface 32.

[0090] Preferably, other properties of adhesive surface 26 arereusability, high internal strength, low dirt pickup, and agingcharacteristics that allow reproducible securing at the image interfaceof adhesive-contacting surface 32 to adhesive surface 26 over a longperiod of time. If possible, good cleanability is also desired. Thereproducible securing should create a good bond at the image interfacebetween adhesive surfaces 26 and adhesive-contacting surface 32 whilealso allowing easy removal without damage to the adhesive surface 26.The combination of adhesive carrier 12 and image carrier 16 need to forma high quality image graphic produced by any manual or mechanical means.

[0091] An advantage of the present invention is that the system allowsthe adhesive and film to be separate components, and thus optimized fora specific application. For adhesive carrier 12, the pressure sensitiveadhesive chosen for surface 22 can be designed for optimum adhesion tothe substrate 14, while the adhesive chosen for adhesive surface 26 canbe very tacky indiscriminately, very tacky discriminately, or of littleor no tack, depending on the duration and environment of usage.

[0092] The system 10 could be seen to have one limitation, namely thatthe system 10 in certain embodiments requires two applications; firstadhesive carrier 12 to the substrate 14, and second image carrier 16 toadhesive carrier 12. While having to do two applications is adisadvantage, this is mitigated by the following factors: first, each ofthe applications is easier. If the adhesive carrier 12 is misalignedduring application, the material can be trimmed square and to the propersize. Wrinkles can be cut out and replaced. Second, the lower adhesionof the image carrier 16 to adhesive carrier 12 (relative to the adhesionof adhesive carrier 12 to substrate 14) allows for easy, bubble-freeapplication of the graphic, and easy removal and reapplication.Consequently, this step is very fast. Third, the system can beeffectively used for image graphics where the adhesive carrier 12 isapplied once, and the image carrier(s) 16 is applied and removednumerous times as the graphic is changed. Thus, the two applications areonly done for the first time a graphic is placed. After that only animage carrier 16 is applied. Fourth, since the removal of the graphicimage is easy and controlled, the time for changing graphics is greatlyreduced. Thus, the system's time advantage is realized as the number ofchanges in the graphic increases.

[0093] Another advantage of the system of the present invention overconventional image graphics where the imaged film is adhesive-backed isthat system 10 has less waste and potentially lower cost for achangeable graphics system. In a conventional adhesive-coated graphic, acustomer must buy three components for each application: a graphic film,a pressure sensitive adhesive and a high quality liner. The liner isthrown away during application, and the pressure sensitive adhesive isdisposed of when removing the graphic. In system 10, adhesive carrier 12is supplied with a liner that also must be thrown away duringapplication. However, the liner for adhesive carrier 12 is much lesscostly because the adhesive carrier 12 does not go through the printprocess, where a high quality liner may be needed for dimensionalstability. The dual layer construction of the adhesive carrier 12 can beseen as consuming slightly more materials than traditional PSA on aconventional graphic only when using the system as a one-timeapplication system. The material savings for the total system 10 occurwhen changing graphics; only the image carrier 16, without adhesive andwithout liner, is disposed to be replaced by a new image carrier,without adhesive and without liner. The adhesive is recycled in place.Further, since a customer only needs to buy another image carrier 16 forsubsequent graphics, money is saved, or can be used to purchase a betterquality film or higher resolution image graphics.

[0094] In comparison to mechanically fastened graphics, the system 10has an important and advantageous attribute: the system 10 preferablyhas the thin caliper and conformability of a conventional pressuresensitive adhesive film graphic. In contrast, mechanically fastenedgraphics have the disadvantage of being relatively thick, bulky, anddifficult to handle. Graphics that use a frame or rigid substrate arelimited to flat applications. Even micromechanical bonding systems suchas hook and loop are still an order of magnitude thicker than a pressuresensitive adhesive graphic. Thus, mechanically fastened graphics can notachieve in most applications the desired “painted-on” look of an adheredgraphic. System 10 preferably has the advantage of retaining the thincaliper that gives the “painted-on” look of the high quality pressuresensitive adhesive graphics. Preferably the total image graphic is lessthan 20 mils thick. More preferably, the total image graphic is lessthan 10 mils thick.

[0095] A second advantage of system 10 over graphics such as hook andloop systems or gross mechanical fasteners such as staples is that thesystem 10 can preferably be used in back-lit graphic applications.Mechanically fastened graphics as described above do not perform well inthis application because they are fairly expensive, they are too thickand do not let light pass through, or the construction is ofintermittent density (i.e.: hook and loop) so that the lighttransmission is uneven. Preferred embodiments of system 10 have theadvantage in that both layers can give uniform light transmission.

[0096] Conventional Application

[0097] In one preferred embodiment of the present invention, the systemis provided in a relatively low cost format utilizing conventional imagecarriers. Materials may be selected such that the system may be used inenvironmentally challenging conditions, or in more controlled, lessdemanding conditions.

[0098] Uses of the image graphic adhesive system 10 in conventionalapplication, environmentally challenging environments requirepredictable durability of the securement of adhesive carrier 12 tosubstrate 14 and the predictable durability of releasably adhered imagecarrier 16 to adhesive carrier 12 until a time of removal orrepositioning. The duration of use for the image carrier 16 in aconventional application, environmentally challenging use ranges fromabout 1 day to about one year and preferably from about 1 week to aboutthree months. Environmentally challenging environments can be outdooruses or indoor uses where strong chemicals are present in the air orultraviolet light is present or temperature extremes are present orhumidity extremes or extreme changes of relative humidity are present.

[0099] “Conventional application” means using an image carrier whichrelies on its inherent release characteristics, e.g., an untreated paperor film. Materials in this category are not as easily repositionable andrequire more removal force as compared to image carriers which havespecial coatings which promote repositionability and easy removal.Conventional application does not lend itself as well to achieving awrinkle-free and bubble-free application, particularly withinexperienced applicators. However, conventional application is verymuch preferred for inexpensive but highly resolved image graphics wherethe use of paper or uncoated film is acceptable as the receiving mediafor the image graphic. Also, conventional application is suitable inthose situations when the image carrier needs to be firmly bonded to theadhesive carrier with reliability.

[0100] Adhesive Carrier Construction

[0101] Nonlimiting examples of adhesives for use on surface 22 ofadhesive carrier 12 to bond to substrate 14 include strong, tackyadhesives such as acrylic adhesives available from 3M and AshlandChemical Company of Columbus, Ohio, USA (such as Aroset™ brandedacrylics); and those constructions disclosed in U.S. Pat. No. 5,196,266and PCT Patent Publication WO 94/21742, the disclosures of which areincorporated by reference herein. Environmentally controlled conditionsallow for a broad selection of adhesives, including rubber adhesives,provided that the required peel strength parameters are met for theoverall system.

[0102] Uses of the image graphic adhesive system 10 in conventionalapplication, environmentally controlled environments require predictabledurability of the bond of adhesive carrier 12 to substrate 14 and thepredictable durability of releasably adhered image carrier 16 toadhesive carrier 12 until a time of removal or repositioning. Typicallysuch environments are indoors and do not require special properties forthe interface between adhesive carrier 12 and image carrier 16 such as arelease coating. The duration for the image carrier 16 ranges from aboutone day to about 24 weeks and preferably from about one weeks to about 6weeks. Environmentally environments can be indoor uses where no strongchemicals are present in the air or low amounts of ultraviolet light arepresent or no temperature extremes and no rain are present.

[0103] Because of the variation in location of the field of pressuresensitive adhesive, not in its formulation, conventional pressuresensitive adhesives presently used for image graphics can be acceptablefor adhesive surface 26 of adhesive carrier 12. Nonlimiting examples ofsuch pressure sensitive adhesives can generally be found in Satas, Ed.Handbook of Pressure Sensitive Adhesives, 2 Ed. (Von Reinhold Nostrand1989). Of these adhesives, desirable adhesives include solvent-basedacrylic and rubber adhesives, water-based acrylic adhesives, hot meltadhesives, microsphere-based adhesives, and silicone-based adhesives,regardless of their method of preparation.

[0104] Coating weights of such adhesives on adhesive carrier 12 canrange from about 10 μm to about 300 μm and preferably about 20 μm toabout 250 μm.

[0105] Percent solids of such adhesives in the formulations to beapplied on layer range from about 5%to about 100% and preferably fromabout 20% to about 100%.

[0106] Of these multitude of pressure sensitive adhesives, a few arepreferred. Among the preferred are acrylic adhesives having permanentlylow tack such as microsphere-based adhesives disclosed in U.S. Pat. Nos.5,141,790 (Calhoun et al.); 5,296,277 (Wilson et al.); 5,362,516 (Wilsonet al.); and EPO Patent Publication EP 0 570 515 B1 (Steelman et al.),the disclosures of which are incorporated by reference herein.

[0107] Typical substrates to which this embodiment of system 10 isapplied include painted metal, polymeric foam board, melamine coatedchipboard, polymethylmethacrylate, glass, and the like.

[0108] For longer duration, environmentally challenging conditions, itis preferable that exposed adhesive on adhesive surface 26 be washableor otherwise capable of being cleaned. Certain Ashland Aroset brand and3M brand adhesives are particularly suitable for cleaning between uses.

[0109] Nonlimiting examples of adhesive integrity layer 24 includethermoplastic materials such as polyolefins and polyesters. Preferably,such polyesters include polyethylene terephthalates and such polyolefinsinclude polypropylenes, especially biaxially oriented polypropylenes.

[0110] Nonlimiting examples of adhesives for use on adhesive surface 26include acrylic adhesives (from the same list as for adhesive surface22, but different than that used in surface 22 to provide differentialadhesion) from 3M and Ashland Chemical Co. and a nontacky adhesive suchas a terpolymer of acrylonitrile, butadiene, and isoprene, or similarcopolymer of acrylonitrile and either butadiene or isoprene,commercially available under the brand Nipol adhesives from ZeonChemical Co, Louisville, Ky., USA and those adhesives disclosed in EPOPatent Publication EP 0 736 585 (Kreckel et al.), which describes aremovable pressure sensitive adhesive that leads to adhesives that canbe used to make pressure sensitive adhesive sheets with differentialadhesion, the stronger adhesive serving on adhesive carrier 12 asadhesive surface 22 and the weaker adhesive serving as adhesive surface26. Moreover, these adhesives are “washable” in that their tackinessdiminished by dirt or other deleterious surface contact can be restoredafter cleaning with common cleaning agents including without limitationrinsing with clean water. Thus, these latter adhesives are desired when“cleanability” is a desired feature.

[0111] Coating weights of such adhesives on adhesive carrier 12 canrange from about 10 gm/m² to about 300 gm/m² and preferably about 20gm/m² to about 150 gm/m².

[0112] Typical substrates to which this embodiment of system 10 isapplied include painted metal, polymeric foam board, and the like.

[0113] Regardless of intended application environment, the percentsolids of such adhesives in the formulations to be applied on layerrange from about 5% to about 100% and preferably from about 20% to about100%.

[0114] The surface area of adhesive surface 26 can be coated as desiredfor the amount of re-usable adhesive surface area. Percentage coverageper unit area can range from about 20 to about 100% and preferably fromabout 50 to about 100%.

[0115] The thickness of adhesive carrier 12 can range from about 12 μmto about 500 μm, and preferably from about 25 μm to about 300 μm.Depending on the number of components in adhesive carrier 12, thatthickness can be composed of an adhesive for surface 22 that ranges fromabout 12 μm to about 200 μm and preferably from about 25 μm to about 125μm; an adhesive integrity layer 24 that ranges from about 0.0 μm toabout 100 μm and preferably from about 12 μm to about 75 μm; and anadhesive for adhesive surface 26 that ranges from about 12 μm to about200 μm and preferably from about 25 μm to about 125 μm.

[0116] Adhesive for surface 22 can be placed on adhesive integrity layer24 using a variety of techniques known to those skilled in the art suchas casting, extruding, coating, spraying, screen-printing andlaminating. Adhesive for adhesive surface 26 can be placed on adhesiveintegrity layer 24 using a variety of techniques known to those skilledin the art such as casting, extruding, coating, spraying,screen-printing and laminating.

[0117] The 20°-180° peel adhesion for the interface between adhesivecarrier 12 and image carrier 16 is greater than the 20°-180° peeladhesion for the interface between adhesive carrier 12 and substrate 14after a dwell time of about 24 hours and preferably ranges from about10% to about 90% of the 20°-180° peel adhesion for the interface betweenadhesive carrier 12 and substrate 14 after a dwell time of about 24hours.

[0118] Preferably, the percentage ranges from about 20 to about 80 inorder to provide ease of removal but sufficient adhesion during use whenmeasured after a 24 hour dwell time.

[0119] Adhesion at interfaces changes over time. Therefore at about 14days of dwell time, the percentage ranges from about 10 to about 90 inorder to provide predictable performance at the respective interfaces,based on choices of adhesives and how such adhesives interact with thesurfaces such adhesive contact over time.

[0120] Typical substrates to which this embodiment of system 10 includepainted metal, polymeric foam board, and the like.

[0121] Image Carrier Construction

[0122] Image carrier 16 should satisfy three requirements. First, itshould bond positively to adhesive surface 26 of adhesive carrier 12without lifting and curling, while still allowing for easy removal.Second, imageable surface 36 should accept a variety of a number of highquality graphic imaging methods including thermal transfer of colorant,inkjet printing, screen printing, offset printing, flexographicprinting, laser printing, electrophotographic printing, electrostatictransfer printing, and combinations thereof. Thirdly, the image carriermust have sufficient internal strength to remove from adhesive surface26 without delaminating or tearing. Preferably, imageable surface 36 canbe tailored to receive specific types of printed image graphics 40,according to the differences in colorants, delivery, and the like. Agingcharacteristics and environmental resistance are important. Inenvironmentally challenging environments, the image needs to be durable,i.e., using pigment-based colorants rather than dye or other colorants.Paper image carriers would be less preferred. However, in thenon-challenging environments, non-release-coated papers and films arepreferred for cost reasons and because there is less need for a robustmaterial to withstand environmental forces.

[0123] The thickness of image carrier 16 can range from about 25 μm toabout 300 μm and preferably from about 50 μm to about 150 μm.

[0124] While some single layer films can work as described above inrelation to FIG. 1, image carrier 16 for the environmentally challengingenvironment having multiple layers 32, 34, and 36 that are extruded atthe same time or have surface treatments or coatings that are appliedafter the film is made are preferred. Nonlimiting examples of imageintegrity layer 34 useful for the present invention in theenvironmentally challenging environment include polymeric films such aspolyesters, polyvinyl chlorides, polyethylenes, polypropylenes, acidneutralized polyacrylic acids, vinyl acetate copolymers, and copolymersor terpolymers including ethylene and polyacrylic acid, where one orboth major surfaces can be preferably treated to improve imaging qualityin the case of imageable surface 36 and adhering quality in the case ofadhesive-contacting surface 32.

[0125] Nonlimiting examples of processing capable of making theimageable surface 36 receptive to imaging include surface modificationtechniques such as Corona Treatment; liquid coatings dissolved orsuspended in either organic solvents or water; or a 100% solidspolymeric material that can be extruded or coextruded onto the imageablesurface 36 either during or after formation of the image carrier 16.Nonlimiting examples of liquid coatings include ethylene vinyl acetatedispersions, alkyd resins in organic solvent, acrylate and urethaneacrylate coatings in water or organic solvents, polyvinyl chloride inorganic solvent, and all of the above combined with inorganic materialssuch as talc, clays, silica and pigments.

[0126] Preferred examples of image integrity layer 34 include polymericfilms and papers on which an image can be placed or printed, such aspolyolefin films, polyester films.

[0127] Adhesive-contacting surface 32 can be treated or not treated tomatch with the adhesive properties of adhesive surface 26 of adhesivecarrier 12. Preferably, adhesive-contacting surface 32 is not treatedfor this embodiment.

[0128] Easy Application

[0129] Uses of the image graphic adhesive system 10 in environmentallychallenging environments require predictable durability of the bond ofadhesive carrier 12 to substrate 14 and the predictable durability ofreleasably adhered image carrier 16 to adhesive carrier 12 until a timeof removal or repositioning. Because the image carrier 16 is to bereleased from the adhesive carrier, a feature of this system 10 is thepresence of a coating or film on surface of the image carrier 16 thatcontacts the adhesive carrier 12 but permits easy release andrepositioning. Duration for the image carrier 16 ranges from about 1 dayto about 6 months and preferably from about one week to about 3 months.Environmentally challenging environments can be outdoor uses or indooruses where strong chemicals are present in the air or ultraviolet lightis present or temperature extremes are present or humidity extremes orextreme changes of relative humidity are present.

[0130] Environmentally non-challenging environments can be indoor useswhere no strong chemicals are present in the air, or low amounts ofultraviolet light are present, or no temperature extremes and no rain orhigh humidity are present.

[0131] “Easy application” means that the image carrier and adhesivecarrier are engineered to provide easy placement and removal of theimage carrier without loss of holding power for the contemplatedduration of the image carrier on the adhesive carrier.

[0132] While the image carrier 16 will be engineered for short duration,the adhesive carrier will remain in place for considerable periods oftime, ranging from months to years depending on length of intended useof the image graphic adhesive system.

[0133] Nonlimiting examples of adhesives for use on surface 22 ofadhesive carrier 12 to bond to substrate 14 include strong, tackyadhesives such as acrylic adhesives available from 3M such as No. 9458and No. 966 adhesive transfer sheets resized into a larger area, andthose adhesives disclosed in EPO Patent Publication EP 0 736 585(Kreckel et al.), which describes a removable pressure sensitiveadhesive that leads to adhesives that can be used to make pressuresensitive adhesive sheets with differential adhesion, the strongeradhesive serving on adhesive carrier 12 as surface 22 and the weakeradhesive serving as adhesive surface 26.

[0134] When transfer sheets 9458 and 966 are used, they can function asthe entire adhesive carrier 12 because the transfer adhesive comprisinga single adhesive composition inherently has highly differing adhesionto an untreated substrate as compared to an image carrier which has beenprovided with an adhesive-repellant release composition.

[0135] When other sheets are used, nonlimiting examples of adhesiveintegrity layer 24 include thermoplastic materials such as polyolefinsand polyesters. Preferably, such polyesters include polyethyleneterephthalates and such polyolefins include polypropylenes.

[0136] Nonlimiting examples of adhesives for use on adhesive surface 26include acrylic adhesives from the same list of sheets as used forsurface 22. Rubber adhesives are also suitable for use inenvironmentally controlled or non-challenging environments.

[0137] Because of the variation in location of the field of pressuresensitive adhesive, not in its formulation, conventional pressuresensitive adhesives presently used for image graphics can be acceptablefor adhesive surface 26 of adhesive carrier 12. Nonlimiting examples ofsuch pressure sensitive adhesives can generally be found in Satas, Ed.Handbook of Pressure Sensitive Adhesives, 2 Ed. (Von Reinhold Nostrand1989). Of these adhesives, desirable adhesives include solvent-basedacrylic and rubber adhesives, water-based acrylic adhesives, hot meltadhesives, microsphere-based adhesives, and silicone-based adhesives,regardless of their method of preparation.

[0138] Coating weights of such continuous layers of adhesives onadhesive carrier 12 can range from about 5 gm/m² to about 300 gm/m² andpreferably about 20 gm/m² to about 150 gm/m².

[0139] Percent solids of such adhesives in the formulations to beapplied on layer range from about 5% to about 100% and preferably fromabout 20 to about 100%.

[0140] Of these multitude of pressure sensitive adhesives, a few arepreferred. Among the preferred are medium to high tack acrylic-basedpressure-sensitive adhesives.

[0141] The thickness of adhesive carrier 12 can range from about 12 μmto about 500 μm, and preferably from about 25 μm to about 300 μm.Depending on the number of components in adhesive carrier 12, thatthickness can be composed of an adhesive for surface 22 that ranges fromabout 12 μm to about 200 μm and preferably from about 25 μm to about 125μm; an adhesive integrity layer 24 that ranges from about 0.0 μm toabout 100 μm and preferably from about 12 μm to about 75 μm; and anadhesive for adhesive surface 26 that ranges from about 12 μm to about200 μm and preferably from about 25 μm to about 125 μm.

[0142] Adhesive for surface 22 can be placed on adhesive integrity layer24 using a variety of techniques known to those skilled in the art suchas casting, extruding, coating, spraying, screen-printing andlaminating. Adhesive for adhesive surface 26 can be placed on adhesiveintegrity layer 24 using a variety of techniques known to those skilledin the art such as casting, extruding, coating, spraying,screen-printing and laminating.

[0143] The 20°-180° peel adhesion for the interface between adhesivecarrier 12 and image carrier 16 ranges from about 0.1 to about 50percent of the 20°-180° peel adhesion for the interface between adhesivecarrier 12 and substrate 14 after a dwell time of about 24 hours.

[0144] Preferably, the percentage ranges from about 1 to about 50 inorder to provide ease of removal but sufficient adhesion during use whenmeasured after a 24 hour dwell time.

[0145] Adhesion at interfaces changes over time. Therefore at about 14days of dwell time, the percentage ranges from about 0.1 to about 50 inorder to provide predictable performance at the respective interfaces,based on choices of adhesives and how such adhesives interact with thesurfaces such adhesive contact over time.

[0146] Typical substrates to which this embodiment of system 10 isapplied include painted metal, polymeric foam board, melamine-coatedchipboard, polymethylmethacrylate, and the like.

[0147] Image Carrier Construction

[0148] Image carrier 16 should satisfy three requirements. First, itshould bond positively to adhesive surface 26 of adhesive carrier 12without lifting and curling, while still allowing for easy removal.Second, imageable surface 36 should accept a variety of a number of highquality graphic imaging methods including thermal transfer of colorant,inkjet printing, screen printing, offset printing, flexographicprinting, laser printing, electrophotographic printing, electrostatictransfer printing, and combinations thereof. Thirdly, the image carriermust have sufficient internal strength to remove from adhesive surface26 without delaminating or tearing. Preferably, imageable surface 36 canbe tailored to receive specific types of printed image graphics 40,according to the differences in colorants, delivery, environmentalconditions, and the like. Aging characteristics and environmentalresistance are important. In environmentally challenging environments,the image needs to be durable, i.e., using pigment-based colorantsrather than dye or other colorants. Paper image carriers would be lesspreferred. However, in the non-challenging environments,non-release-coated papers and films are preferred for cost reasons andbecause there is less need for a robust material to withstandenvironmental forces.

[0149] The thickness of image carrier 16 can range from about 25 μm toabout 300 μm, and preferably from about 50 μm to about 150 μm. Dependingon the number of components in image carrier 16, that thickness can becomposed of a release coating for adhesive-contacting surface 32 thatranges from about 0.1 μm to about 25 μm and preferably from about 0.5 μmto about 20 μm; an integrity layer 34 that ranges from about 25 μm toabout 300 μm and preferably from about 50 μm to about 150 μm; and animageable surface 36 that ranges from about 0 μm to about 50 μm andpreferably from about 5 μm to about 25 μm. Thicknesses will increase ifimage carrier 16 takes the form a multilayer film as now discussed.

[0150] While some single layer films can work as described above inrelation to FIG. 1, image carrier 16 having multiple layers 32, 34, and36 that are extruded at the same time or have surface treatments thatare applied after the film is made are preferred.

[0151] Nonlimiting examples of image integrity layer 34 that areparticularly preferred for use in environmentally challenging conditionsinclude polymeric films such as polyesters, polyvinyl chlorides,polyethylenes, polypropylenes, acid neutralized polyacrylic acids, vinylacetate copolymers, and copolymers or terpolymers including ethylene andacrylic acid, where one or both major surfaces can be preferably treatedto improve imaging quality in the case of imageable surface 36 andadhering quality in the case of adhesive-contacting surface 32.

[0152] In the easy application, environmentally controlled applicationembodiment, the use of siliconized papers and films is preferred.

[0153] Nonlimiting examples of image integrity layer 34 useful for theenvironmentally controlled embodiment include siliconized paper andpolymeric films such as polyesters, polyvinyl chlorides, polyethylenes,polypropylenes, acid neutralized polyacrylic acids, and vinyl acetatecopolymers, where one or both major surfaces can be preferably treatedto improve imaging quality in the case of imageable surface 36 andadhering quality in the case of adhesive-contacting surface 32.

[0154] Regardless of the environment of intended use, nonlimitingexamples of processing capable of making the imageable surface 36receptive to imaging include surface modification techniques such asCorona Treatment; liquid coatings dissolved or suspended in eitherorganic solvents or water; or a 100% solids polymeric material that canbe extruded or coextruded onto the imageable surface 36 either during orafter formation of the image carrier 16. Nonlimiting examples of liquidcoatings include ethylene vinyl acetate dispersions, alkyd resins inorganic solvent, acrylate and urethane acrylate coatings in water ororganic solvents, polyvinyl chloride in organic solvent, and all of theabove combined with inorganic materials such as talc, clays, silica andpigments.

[0155] Preferred examples of integrity layer 34 for use inenvironmentally challenging conditions include polymeric films andpapers on which an image can be placed or printed, such as polyolefinfilms.

[0156] Further image carrier 16 of the present invention can includenaturally and synthetically-modified cellulosics, where it is preferredto have adhesive-contacting surface 32 treated with asilicone-containing release material to improve repositionability andremovability of the image carrier 16 on the adhesive carrier 12.

[0157] As stated above,-adhesive-contacting surface 32 is treated with arelease coating. Nonlimiting examples of such coatings includesilicones, polyethylenes, fluorosilicones and so-called low adhesion“backsize” materials (e.g. carbamates, siliconeureas, acrylates,) knownto those skilled in the art.

[0158] Easy Application, Environmentally Controlled Uses

[0159] Uses of the image graphic adhesive system 10 in environmentallyenvironments require predictable durability of the bond of adhesivecarrier 12 to substrate 14 and the predictable durability of releasablyadhered image carrier 16 to adhesive carrier 12 until a time of removalor repositioning. Moreover, the ease of application becomes importantfor the user of the product. As such, adhesive-contacting surface 32 istreated with a release coating to assist in the placement and removal ofimage carrier 16 from adhesive carrier. The duration for the imagecarrier 16 residing on adhesive carrier 12 ranges from about 1 day toabout six months and preferably from about one week to about threemonths.

[0160] Nonlimiting examples of adhesives for use on surface 22 ofadhesive carrier 12 to bond to substrate 14 include strong, tackyadhesives such as acrylic adhesives available from 3M and rubberadhesives.

[0161] Image Formation

[0162] Surface 36 of image graphic film 16 requires characteristics thatpermit imaging using at least one of the known imaging techniques.Nonlimiting examples of imaging techniques include solvent- andwater-based inks, 100% solids ultraviolet curable inks, inkjet printing,thermal transfer, screen printing, offset printing, flexographicprinting, and electrostatic transfer imaging.

[0163] Digital Imaging: Electrostatic Hardware and Software

[0164] Electrostatic transfer for digital imaging employs a computer togenerate an electronic digital image, an electrostatic printer toconvert the electronic digital image to a multicolor toned image on atransfer medium, and a laminator to transfer the toned image to adurable substrate. Electrostatic transfer processes are disclosed inU.S. Pat. Nos. 5,045,391 (Brandt et al.); 5,262,259 (Chou et al.);5,106,710 (Wang et al.); 5,114,520 (Wang et al.); and 5,071,728 (Wattset al.), the disclosures of which are incorporated by reference herein,and are used in the Scotchprint™ electronic imaging process commerciallyavailable from 3M.

[0165] Nonlimiting examples of electrostatic printing systems includethe Scotchprint™ Electronic Graphics System from 3M. This system employsthe use of personal computers and electronically stored and manipulatedimages. Nonlimiting examples of electrostatic printers are single-passprinters (Models 9510 and 9512 from Nippon Steel Corporation of Tokyo,Japan and the Scotchprint™ 2000 Electrostatic Printer from 3M) andmultiple-pass printers (Model 8900 Series printers from XeroxCorporation of Rochester N.Y., USA and Model 5400 Series from RasterGraphics of San Jose, Calif., USA)

[0166] Nonlimiting examples of electrostatic toners include Series 8700toners from 3M. Nonlimiting examples of transfer media include Model8600 media (e.g., 8601, 8603, and 8605) from 3M.

[0167] Nonlimiting examples of laminators for transfer of the digitalelectrostatic image include Orca III laminator from GBC Protec,DeForest, Wis.

[0168] Nonlimiting examples of protective layers include liquid-applied“clears” or overlaminate films. Nonlimiting examples of protectiveclears include the 8900 Series Scotchcal™ Protective Overlaminatematerials from 3M. Nonlimiting examples of protective overlaminatesinclude those materials disclosed in U.S. Pat. No. 5,681,660 (Bull etal.) and copending, coassigned, PCT U.S. pat. application Ser. No.96/07079 (Bull et al.) designating the USA and those materials marketedby 3M as Scotchprint™ 8626 and 3645 Overlaminate Films.

[0169] Digital Imaging: Ink Jet Hardware and Software

[0170] Thermal ink jet hardware is commercially available from a numberof multinational companies, including without limitation,Hewlett-Packard Corporation of Palo Alto, Calif., USA; Encad Corporationof San Diego, Calif., USA; Xerox Corporation of Rochester, N.Y., USA;LaserMaster Corporation of Eden Prairie, Minn., USA; and MimakiEngineering Co., Ltd. of Tokyo, Japan. The number and variety ofprinters changes rapidly as printer makers are constantly improvingtheir products for consumers. Printers are made both in desk-top sizeand wide format size depending on the size of the finished graphicdesired. Nonlimiting examples of popular commercial scale thermal inkjet printers are Encad's NovaJet Pro printers and H-P's 650C and 750Cprinters. Nonlimiting examples of popular desk-top thermal ink jetprinters include H-P's DeskJet printers.

[0171] Piezo inkjet print heads are commercially available from TopazTechnologies (Sunnyvale, Calif.), Epson Corporation (Torrance, Calif.),Data Products (Woodland Hills, Calif.), Modular Ink Technologies(Dallas, Tex.), and others. These printheads differ in physicalproperties such as frequency and drop volume and the inks to be used inthem often require different physical properties such as viscosity. Suchprint heads are used in piezo inkjet printers commercially availablefrom Scitex/Idanit Technologies, Ltd. of Rishon Le Zion Israel; RasterGraphics of San Jose, Calif.; Vutek Inc. of Meredith, N.H.; OlympusOptical Co. Ltd. of Tokyo, Japan and others.

[0172] 3M markets Graphic Maker Ink Jet software useful in convertingdigital images from the Internet, ClipArt, or Digital Camera sourcesinto signals to thermal ink jet printers to print such images.

[0173] Ink jet inks are also commercially available from a number ofmultinational companies, particularly 3M which markets its Series 8551;8552; 8553; and 8554 pigmented ink jet inks. The use of four principalcolors: cyan, magenta, yellow, and black permit the formation of as manyas 256 colors or more in the digital image.

[0174] Lithographic and Offset Printing

[0175] Flexographic and offset printing are also well known to thoseskilled in the art as explained in U.S. Pat. Nos. 5,322,761 (Kausch etal.) and 5,015,556 (Martens) for the former and U.S. Pat. Nos. 4,225,663(Ball) and 5,670,294 (Piro) for the latter; all of which areincorporated herein by reference.

[0176] Thermal Transfer Printing

[0177] Thermal transfer procedures are well known to those skilled inthe art as explained in U.S. Pat. Nos. 5,747,217 (Zaklika et al.);5,843,617 (Chambers et al.); and 5,326,619 (Debe et al.), thedisclosures of which are incorporated by reference herein.

[0178] Other Printing Means

[0179] Mechanical means of printing such as handwriting orelectrophotographic means of printing such as photocopying can also beused. Moreover, laser printing techniques can also be used.

[0180] Uses of Image Graphics

[0181] Depending on the duration and environment for which the imagegraphic adhesive system is designed, image graphics can be displayed ina multitude of locations. One skilled in the art can choose from thematrix of possible embodiments to best fit the use of the image graphicwith the environment and application effort desired. Any advertisingthat depends on changing graphics can benefit from this invention, suchas point-of-purchase displays, sales promotion posters, and the like.Likewise, information that depends on changing graphics, such asannouncements in office, school, and public buildings, also can use thesystem. The system is primarily designed for walls and other verticalsurfaces, although it is possible to use the system on horizontalsurfaces if the adhesive surface 26 is not adversely affected. Thesystem can be front-lit or back-lit, because embodiments of the systemcan provide for opaque, translucent, or transparent construction of theadhesive carrier 12 and the image carrier 16. In other words, the systemcan be applied to industrial and consumer use by those skilled in theart in any possible variation to advantage of ease of installation andremoval.

[0182] Other embodiments will become apparent from the followingexamples using the following tests.

TEST METHODS

[0183] 90° Peel Adhesion

[0184] 90° Peel adhesion tests were performed for all examples for (1)adhesive carrier to substrate bonds and (2) image carrier to adhesivecarrier bonds. The test was performed using DIN (Deutsche Industrie NormEN 28510 Part 1). The rate of peel was 300 mm/min.; the width of thematerial being removed was 2.54 cm.

[0185] 180° Peel Adhesion

[0186] Adhesive bonds were prepared as above under 90° Peel Adhesion.Peel force of the siliconized image carriers from the adhesive layer wasmeasured at a high rate of 2.8 m/min DIN (Deutsche Industrie Norm EN28510 Part 2)

[0187] For both Peel Adhesion tests, three samples were measured insteadof five as specified in the DIN test method. All samples were overrolledat the rate of 300 mm/min. which is not specified in the DIN testmethod. The dwell times and choice of substrates varied according thefollowing Examples.

EXAMPLES Example 1

[0188] A painted sheet metal sign board designed for the display ofadvertising graphics was chosen as a substrate. The two surfaces usedfor mounting graphics were made of painted steel and had dimensions of85 cm×60 cm.

[0189] A DIN A4 (21 cm×29.7 cm) sheet of double-coated adhesive sheethaving a high tack acrylic PSA on one side and a low tack acrylic PSA onthe other side, available as Tape No. 9415 High Tack/Low TackDouble-Coated Tape from 3M Company, St. Paul, Minn., USA, was laminatedto cover a portion of one of the two surfaces of the advertising board.The sheet, available in roll form with a single liner applied to the lowadhesion side of the sheet, was unrolled and cut to the appropriatesize. The unlinered high-adhesion side was applied to the painted metalsurface using a rubber-coated roller. The liner was removed from the lowadhesion side. A sheet of recyclable notepad paper (50 g, available asNo 367405008 from Landré of Vianen, the Netherlands) bearing a handwritten message and having the same dimensions as the exposed adhesiveon the advertising board was applied to the exposed low adhesion side ofthe double-coated adhesive sheet by hand.

[0190] The paper image graphic could be easily removed from the adhesivesurface after 24 hours and be reapplied. Since the paper had littlememory, it did not curl at the edges on removal from the adhesive. Noedge lift occurred after reapplication. The double-coated adhesive sheetwas removable from the substrate after several weeks of storage at roomtemperature and ambient humidity.

[0191] The peel adhesion of the adhesive carrier from the substrate andthe peel adhesion of the image graphic from the adhesive carrier wereevaluated quantitatively by the 90° peel adhesion test (performedaccording to the method described under Test Methods, above).

Comparative Example 1

[0192] Example 1 was repeated with the exception that the low adhesionside of the double-coated adhesive sheet was applied to the paintedmetal substrate. This was accomplished by first applying a second linerto the high adhesion side, stripping the liner from the low adhesionside and applying the adhesive thus exposed to the painted metalsubstrate. The liner was then removed from the high adhesion side andthe paper was then applied to the higher adhesion side of the adhesivesheet.

[0193] The paper image graphic was not removable after a dwell time of30 seconds and tore during attempts to remove the paper. The lowadhesion side of the double-coated adhesive sheet lifted partially fromthe substrate when attempts were made to remove the paper from the highadhesion side of the sheet.

Example 2

[0194] Example 1 was repeated with the exception that a sheet of papersuitable for use with a black and white photocopier (available asFAVORIT X, No. 9366/080/05/04-80 g) was printed with an image using aphotocopier. The paper bearing the photocopied image was used as animage graphic.

[0195] The image graphic was then laminated by hand to the exposed lowadhesion side of the double-coated adhesive double-coated adhesive sheetafter removal of the liner. The printed paper image graphic wasremovable from the adhesive surface after 24 hours with no lifting ofthe double-coated adhesive sheet from the substrate.

Example 3

[0196] Example 1 was repeated with the exception that a sheet of papersuitable for use with a laser printer (available as FAVORIT X, No.9366/080/05/04-80 g) was printed with an image using a laser printer.The printed paper was used as an image graphic.

[0197] The image graphic was then laminated by hand to the exposed lowadhesion side of the double-coated adhesive after removal of the liner.The printed paper image graphic was removable from the adhesive surfaceafter 24 hours with no lifting of the double-coated adhesive sheet fromthe substrate.

Example 4

[0198] Example 1 was repeated with the exception that a printable filmconsisting of a 60μ thick, white biaxially-oriented polypropylene(BOPP), a three layer film comprising a core layer of cavitatedpolypropylene, commercially available as LABELYTE 60 LL 247 from MobilPlastics, was printed with a red 3M logo using one-color sheet offsetprinting, thus forming the image graphic. The image was applied to theside of the film made suitable for printing by corona treatment. Theimage graphic was applied by adhering the non-printed side to the lowadhesion side of the double-coated adhesive sheet.

[0199] Tests results showed that the image graphic comprising a printedfilm could be removed easily after application and reapplied. There wasno lifting of the double-coated adhesive sheet from the substrate duringremoval of the film and the film was removed cleanly from the adhesivesurface. No adhesive residue was present on the image graphic afterremoval, and no edge curling of the film was observed.

Example 5

[0200] 3M Scotchcal™ Film 3500, comprising a 100 micron thickplasticized PVC backing and an acrylic PSA, was coated with a 5 micronlayer of primer on the non-adhesive coated side. A double-coatedadhesive sheet was prepared by laminating 3M removable transfer adhesive9449 to primed film of the sheet just prepared.

[0201] The double-coated adhesive sheet was applied to the advertisingboard as described in Example 1 with the higher-adhesion originalScotchcal™ adhesive towards the substrate.

[0202] An image graphic was prepared by printing a graphic image onto asheet of paper printable by electrostatic methods, available as #8612Electrostatic Paper from 3M Company, St. Paul, Minn., USA, using anelectrostatic printing process known as SCOTCHPRINT™ Electronic GraphicSystem from 3M. The image graphic thus created was applied to theexposed lower adhesion side of the double-coated adhesive sheet. Theimage graphic was removable from the adhesive surface without liftingthe adhesive from the substrate. The double-coated adhesive sheet ofExample 5 was removable from the substrate as well with less force ascompared to the adhesive of Examples 1-4.

Example 6

[0203] An 8 mm thick, rigid signboard made of foamed polyvinyl chloridewith a slightly textured surface, commercially available as FOREX™ fromAirex AG (Sins, Switzerland) was employed as a substrate. The doublecoated adhesive sheet of Example 5 was applied to the Forex (TM) boardas described in Example 1 with the original Scotchcal adhesive towardsthe substrate.

[0204] An image graphic was created by screen-printing onto a glossycoated graphic paper, available as Ikonorex I 5695 (115 g) from Zanders(Bergisch-Gladbach, Germany). The graphic was applied to the exposedlower adhesion side of the double-coated adhesive sheet. The imagegraphic was removable from the adhesive surface without lifting thedouble-coated adhesive sheet from the substrate. The double-coatedadhesive sheet was removable in one piece from the Forex substratewithout damaging it and leaving no adhesive residue.

Example 7

[0205] A double-coated adhesive sheet was prepared by first coating alayer of mixture of 90 parts by weight of a first water-based acrylicpressure-sensitive adhesive (available as Acronal 35D from BASF) and 10parts by weight of a second water-based acrylic pressure-sensitive,(available as Acronal A 213 S from BASF), onto one side of a 376 μmpolyethylene terephthalate (PET) film, commercially available asHostaphan RN 36 from Hoechst, which had been corona-treated on bothsides. The adhesive was first thickened with 1% by weight Collacral PUfrom BASF and then applied to the film by knife-coating at a dry coatingthickness of about 50 microns and the dried in a forced air oven at 100°C. for about 5 minutes. A release liner was laminated to the driedadhesive layer.

[0206] The single-coated sheet thus prepared was coated on the otherside with a water-based acrylic pressure-sensitive, available as AcronalA 213 S from BASF, which was first thickened, then coated and dried asabove, thus providing a double-coated adhesive sheet. The second side ofthe sheet, also protected temporarily with a liner, had higher adhesion.

[0207] The double-coated adhesive sheet was applied to the substratewith the higher adhesion side toward the substrate.

[0208] An image graphic was prepared by offset printing onto a 115 gmatte graphic paper for offset printing, available as OPUS No. 1370 1150510 from Smurfrit Condat (Finland) and applied to the exposed adhesive.

[0209] The image graphic was removed from the adhesive surface. Theadhesive surface was then deliberately contaminated with particulatemanner consisting of a mixture of 38.4% by weight peat, 18.0% by weightcement, 18.0% kaolin and 18.0% diatomaceous earth, 6.25% mineral oil and1.05% carbon black and 0.3% ferrous oxide. One gram of the above mixturewas sprinkled evenly onto an adhesive sheet measuring 15 cm×15 cm. Thecontaminated surface was then washed with a dilute aqueous soapsolution, rinsed and allowed to dry and the image graphic was reapplied.Adhesion values of the cleaned adhesive surface had returned to 80% ofthe uncontaminated value. This process of removal, cleaning, andreactivation of the adhesive could be repeated as many as 10 timeswithout adhesion values declining more than about 30%.

Example 8

[0210] A double-coated adhesive sheet was prepared in two steps by firstcoating a layer of mixture of 90 parts by weight of a first water-basedacrylic pressure-sensitive adhesive, available as ACRONAL 35D from BASF,and 10 parts by weight of a second water-based acrylicpressure-sensitive, available as ACRONAL A 213 S from BASF, onto oneside of a 36 μ polyethylene terephthalate (PET) film, commerciallyavailable as HOSTAPHAN RN 36 from Hoechst, which had been corona treatedon both sides. The adhesive mixture was first thickened with 1% byweight Collacral PU from BASF and then applied to the film byknife-coating at a thickness to provide a dry coating thickness of about50 microns and dried in a forced air oven at 100° C. for about 5minutes. A release liner was laminated to the dried adhesive layer.

[0211] The single-coated sheet thus prepared was laminated to an acrylictransfer sheet, available from 3M Company as 9470 Adhesive TransferTape. The double-coated adhesive sheet was applied to Forex with the9470 Transfer Tape side towards the Forex substrate.

[0212] An image graphic was prepared by offset printing onto a 115 gmatte graphic paper for offset printing, available as OPUS No. 1370 1150510 from Smurfrit Condat (Finland). The image graphic was applied tothe exposed adhesive.

[0213] The image graphic was removable from the double-coated adhesivesheet. The double-coated adhesive sheet was also removable from theFOREX substrate, but with very high force required.

Comparative Example 2

[0214] A double-coated adhesive sheet was prepared by first coating alayer of a water-based acrylic pressure-sensitive adhesive, available asACRONAL 35D from BASF, onto one side of a 36μ polyethylene terephthalatefilm, commercially available as HOSTAPHAN RN 36 from Hoechst, which hadbeen corona treated on both sides. The adhesive was first thickened with1% by weight Collacral PU from BASF, then applied to the film byknife-coating at a dry coating thickness of about 50 microns and thedried in a forced air oven at 100° C. for about 10 minutes. A releaseliner was laminated to the dried adhesive layer. This adhesive layer hadlower adhesion.

[0215] The single-coated sheet thus prepared was coated on the otherside with a water-based acrylic pressure-sensitive, available as ACRONALA 213 S from BASF, which was thickened, coated and dried as above, thusproviding a double-coated adhesive sheet. This second side of the sheethad higher adhesion.

[0216] The double-coated adhesive sheet was applied to the substratewith the higher adhesion side toward the substrate.

[0217] The image graphic was prepared by offset printing onto a 115 gmatte graphic paper for offset printing, available as OPUS No. 1370 1150510 from Smurfrit Condat (Finland).

[0218] The image graphic was adhered to the exposed adhesive layerhaving lower adhesion. The paper image graphic did not adheresufficiently to the adhesive, however. The image graphic could notsupport its own weight in a vertical position and fell off of its ownaccord, indicating that the peel adhesion value for the image graphic tothe adhesive carrier was too low.

Example 9

[0219] A 32 micron clear, corona-treated biaxially-orientedpolypropylene (BOPP) (available as Propafilm LMO 30 from ICI) ishot-melt coated with a 50 micron layer of rubber/resin basedpressure-sensitive adhesive comprising 33 parts by weight syntheticrubber (available as CARIFLEX TR 1107 from Shell), 44 parts hydrocarbonresin (Escorez 1310 from Exxon Chemicals) and 22 parts polyterpene resin(available as Zonarez A25 from Arizona Chemicals).

[0220] The other side of the BOPP film was coated in the same mannerwith a 50 micron layer of rubber/resin based pressure-sensitive adhesiveavailable as Durotak H1525 from National Starch.

[0221] The adhesive side of the double-coated adhesive sheet based onCariflex was then applied to a melamine-coated chipboard panel.

[0222] The image carrier of Examples 8 and C2 (offset printed paper) wasthen adhered to the exposed adhesive of the double-coated adhesivesheet.

[0223] The image graphic, a matte-finished high strength paper, wasremovable from the rubber/resin adhesive, even though adhesion valueswere, in general, higher than those measured with acrylic adhesivesystems used for adhesion to the image graphic.

Example 10

[0224] A clear double-coated adhesive sheet was prepared by coating apolymer-containing syrup (90 parts by weight isooctyl acrylate, 10 partsby weight fumed silica (AEROSIL R972 from Degussa and 0.2 parts byweight photoinitiator (available as IRGACURE 651 from Ciba-Geigy) onto apolyester carrier as described in Example 5. Each of the sides of thepolyester carrier was coated simultaneously via knife coating with twoslightly differing polymeric syrups, each at a thickness of 100 microns.The syrup-coated polyester was then protected between two siliconizedpolyethylene terephthalate (PET) liners and the adhesive syrups thencured using UV radiation as described in European Patent Application EP0 736 585.

[0225] The syrup used for one side contained, in addition to thecomponents mentioned above, 2.0% tetrapropylene glycol diacrylate(TPGDA) crosslinking agent. The syrup used for the other side contained0.5% TPGDA crosslinking agent. The adhesive layer having the loweramount of crosslinker had higher adhesion.

[0226] The double-coated adhesive sheet thus prepared was applied to an8 mm thick transparent sheet of polymethylmethacrylate (PMMA) byremoving the liner from the adhesive side made with 0.5% crosslinkingagent (higher adhesion side) and laminating the adhesive to thepolymethylmethacrylate sheet. The double-coated adhesive applied to thePMMA formed a clear assembly.

[0227] The image graphic was prepared by flexographic printing on a 80μwhite coextruded biaxially-oriented cavitated polypropylene film (BOPP),available as TRESPAPHAN OWD 80 from Hoechst-Trespaphan (Neunkirchen,Germany). The printable side of the film had been corona-treated.

[0228] The image graphic was applied to the double-coated adhesive sheetin such a fashion that the imaged side was in contact with the exposedadhesive face of the double-coated adhesive sheet. Because of the clearsubstrate and the clear double-coated adhesive sheet, the image could beviewed through the substrate.

Example 11

[0229] Example 10 was repeated with the exception that the image graphicwas printed on both sides. The image on the first side of the imagecarrier could be viewed through the PMMA substrate and the cleardouble-coated adhesive sheet. The image on the second side of the imagecarrier could be viewed from the other side

Example 12

[0230] A double-coated adhesive was prepared using a 80μ whitebiaxially-oriented coextruded, cavitated polypropylene film (BOPP),available as TRESPAPHAN OWD 80 from Hoechst-Trespaphan (Neunkirchen,Germany), as a carrier for the double-coated adhesive sheet. Theprintable side of the film had been corona-treated and was printed withan image by flexographic printing. The printed carrier wascorona-treated on both sides.

[0231] The printed adhesive carrier thus prepared was coated with apolymer-containing syrup on both sides and simultaneously covered withtwo siliconized polyethylene terephthalate (PET) liners. Thesyrup-coated carrier (with liners) was subjected to UV radiation topolymerize the syrup as described in EP 0 736 585. The coating andpolymerization process as well as the chemical composition of the twoadhesive syrups was identical to that described in Example 10.

[0232] The adhesive layer of the double coated having the lesser amountof crosslinker (0.5%) was applied to the glass substrate.

[0233] An image graphic was prepared by printing a paper (available asOPUS No. 1370 115 0510, 115 g matte graphic paper from Smurfrit Condat)using ink-jet printing technology. Such a paper graphic was applied tothe more highly crosslinked adhesive coating of the adhesive carrier andcould be removed as shown in Table 2.

[0234] The double-coated adhesive sheet was removable from the substrateand the image graphic was removable from the double-coated adhesivesheet. The printing on the carrier of the double-coated adhesive sheetcould clearly be seen through the glass substrate, displaying a firstmessage through the glass, while at the same time bearing a removableand changeable image graphic on the other face.

Example 13

[0235] Example 12 was repeated, with the exception that the imagecarrier was printed using thermal transfer technology TABLE 1Conventional Application/Environment SHEET PSA PSA (adhered to IMAGE(adhered to image GRAPHIC Ex. SUBSTRATE substrate) Carrier graphic)Sheet Image 1 Painted metal acrylic polyester acrylic paper hand-writtenC1 ″ acrylic polyester acrylic paper hand-written 2 ″ acrylic polyesteracrylic paper photocopy 3 ″ ″ ″ ″ ″ laser print 4 ″ ″ ″ ″ film offsetprinting 5 ″ acrylic PVC acrylic paper electrostatic printing 6 PVC-foamboard ″ PVC ″ paper screen-printing 7 ″ acrylic polyester acrylic paperoffset printing 8 ″ acrylic polyester acrylic paper offset printing C2 ″acrylic polyester acrylic paper offset printing 9 melamine coated rubberBOPP rubber paper offset chipboard printing 10  PMMA acrylic polyesteracrylic film flexographic printing 11  PMMA ″ polyester ″ filmflexographic printing 12  glass ″ BOPP ″ paper ink-jet printing(printed) 13  glass acrylic BOPP acrylic paper thermal (printed)transfer printing

[0236] TABLE 2 90° Peel adhesion 90° Peel adhesion Double-coatedDouble-coated adhesive sheet from adhesive sheet from 90° Peel adhesionsubstrate substrate 90° Peel adhesion Image Graphic from PSA (N/2.54 cm,24 h (N/2.54 cm, 14 d Image graphic from PSA (N/2.54 cm, 14 d Ex. dwell)dwell) (N/2.54 cm, 24 h dwell) dwell) 1 9.47 11.23  1.81 1.92 C1 0.781.23 Paper Split Paper Split 2 9.47 11.23  1.58 1.89 3 9.47 11.23  1.581.89 4 9.47 11.23  0.44 0.48 5 5.85 3.73 0.47 0.59 6 5.76 6.28 1.23 1.327 5.55 5.70 1.73 3.31 8 12.69  14.56  1.73 3.31 C2 5.55 5.70 falls offfalls off 9 12.15  14.01  5.63 6.09 10  9.34 13.72  2.78 3.35 11  9.3413.72  2.78 3.35 12  4.48 6.28 2.55 3.29 13  4.48 6.28 2.55 3.29

Example 14

[0237] A painted sheet metal sign board designed for the display ofadvertising graphics was chosen as a substrate.

[0238] A DIN A4 (21.0 cm×29.7 cm) sheet of double-coated adhesive havinga high tack acrylic PSA on one side and a low tack acrylic PSA on theother side, available as Tape No. 9415 High Tack/Low Tack Double-CoatedTape from 3M Company, St. Paul, Minn., USA, was laminated to cover aportion one of the two surfaces of the advertising board. The sheet,available in roll form with a single liner on the low adhesion side, wasfirst unrolled and cut to the appropriate size. A second liner was thenadhered to the high adhesion side. The liner was then removed from thelow adhesion side and the adhesive adhered to the painted steelsubstrate using a rubber-coated roller.

[0239] An image graphic was prepared by writing a message by hand usinga felt-tipped tipped marking pen on a siliconized paper, available as 75g Release PMC (standard low release level) from Lohjan Paperi (Finland).The paper was siliconized only on one side and the writing was appliedto the non-siliconized surface of the paper.

[0240] The image graphic was then adhered to the double-coated adhesivesheet with the silicone-coated side of the image carrier against theexposed higher adhesion side of the double-coated sheet.

[0241] The image carrier was easily removable from the high adhesionsurface without tearing the image graphic or distorting it. Thedouble-coated adhesive sheet remained adhered to the substrate duringremoval of the graphic although a lower tack adhesive was applied to thesubstrate. The double-coated adhesive sheet was removable from thesubstrate.

[0242] The peel adhesion of the adhesive carrier from the substrate wasevaluated quantitatively by the 90° peel adhesion test (performedaccording to the method described under Test Methods, above) and thepeel adhesion of the image graphic from the adhesive carrier wasevaluated quantitatively by the 180° peel adhesion test (performedaccording to the method described under Test Methods, above).

Example 15

[0243] Example 14 was repeated with the exception that thesiliconized-paper image carrier was imaged on the non-siliconized sideusing a photocopier. Essentially the same results were obtained as inExample 14.

Example 16

[0244] Example 14 was repeated with the exception that thesiliconized-paper image carrier was imaged on the non-siliconized sideusing a laser printer. Essentially the same results were obtained as inExample 14.

Example 17

[0245] Example 14 was repeated with the exception that thesiliconized-paper image carrier was imaged on the non-siliconized sideusing offset printing. Essentially the same results were obtained as inExample 14.

Comparative Example 3

[0246] Example 14 was repeated with the exception that the double-coatedadhesive sheet was applied to the substrate with the high adhesion sidefacing the substrate.

[0247] The image graphic was placed on the exposed lower adhesion sideand was not securely adhered. When the assembly was placed in thevertical position, the graphic could not support its own weight andseparated from the adhesive without application of any external peelforces. The double-coated adhesive sheet could be removed from thesubstrate cleanly, but the forces were very high.

Example 18

[0248] Example 14 was repeated with the exception that a secondsiliconized paper, available as 75 g Release PMC MR30 (high releasesystem) from Lohjan Paperi (Finland), was screen printed on thenon-siliconized side and used as an image graphic.

[0249] The image graphic was then adhered to the double-coated adhesivesheet with the silicone-coated side of the image carrier against thehigher adhesion side of the double-coated adhesive sheet. The adhesionwas sufficient to securely bond the image graphic to the substrate.

[0250] The image carrier was cleanly removable from the adhesive surfacewithout tearing the image graphic or distorting it. The double-coatedadhesive sheet remained adhered to the substrate during removal of thegraphic, but could itself be removed from the substrate as well.

Example 19

[0251] Example 14 was repeated with the exception that the image graphiccomprised a 90 g paper, available as Silox 90 CL from Akrosil (Heerlen,The Netherlands). The image graphic, prepared by ink-jet printing on thenon-siliconized surface of the paper, was applied to the high adhesionside of the double-coated adhesive sheet, again as in Example 14. Theimage quality and handleability of the graphic prepared on this paperwas superior (to the one use in ex. 14) for the intended use.

[0252] The image carrier was easily removable from the adhesive surfacewithout tearing the image graphic or distorting it. The double-coatedadhesive sheet remained adhered to the substrate during removal of thegraphic, but could be removed from the substrate as well.

Example 20

[0253] A double-coated adhesive sheet was prepared by first coating alayer of water-based acrylic pressure-sensitive adhesive, available asACRONAL A 213 S from BASF (thickened with 1% by weight Collacral PU fromBASF), onto a siliconized release liner and drying it in a forced airoven. The thickness of the dried adhesive layer was about 50 microns.

[0254] The layer of adhesive thus prepared was then laminated to thenon-adhesive side of a plasticized polyvinyl chloride sheet bearing alayer of acrylic adhesive, available as Scotchcal™ 3500 GraphicFilm/White from 3M Company, St. Paul, Minn., USA, to form adouble-coated adhesive sheet.

[0255] The double-coated adhesive sheet was adhered to the substrate, ahard PVC foam display board, available as Forex™ from Airex AG (Sins,Switzerland). The acrylic adhesive forming an original part of theScotchcal™ film was applied to the substrate.

[0256] An image graphic was prepared by four-color offset printing onthe paper side of a 50 g polyethylene-coated paper No. 67850/60-30,available from PKL (Linnich, Germany). The polyethylene side of theimage graphic was then adhered to the exposed surface of thedouble-coated adhesive sheet

[0257] The image carrier was removable from the adhesive surface and thedouble-coated adhesive sheet was removable from the substrate. InExample 20, the image graphic released with a smooth peel with moresecure adhesion as compared to Example 19.

Comparative Example 4

[0258] Example 20 was repeated with the exception that thepolyethylene-coated paper was applied with the non-PE-coated side to theexposed adhesive surface of the double-coated adhesive sheet.

[0259] The polyethylene-coated paper was not removable from the adhesiveand attempts to remove it resulted in tearing of the image graphic.

Comparative Example 5

[0260] A DIN A4 sheet (21 cm×29.7 cm) of double-coated adhesive having ahigh tack acrylic PSA on one side and a low tack acrylic PSA on theother side, available as 9415 High Tack/Low Tack Double-Coated Tape from3M Company, St. Paul, Minn., USA, was laminated to cover one of the twopainted steel surfaces of the advertising board described in Example 14.The liner was removed from the lower adhesion side and then the loweradhesion side was applied to the painted metal surface using arubber-coated roller.

[0261] An image graphic was prepared by four-color offset printing onthe paper side of a 50 g polyethylene-coated paper No. 67850/60-30,available from PKL (Linnich, Germany). It was then laminated with thecoated side against the image carrier.

[0262] The polyethylene-coated paper was not removable from the highadhesion side of the 3M No. #9415 double-coated adhesive sheet. Liftingof the low adhesion side from the substrate occurred when attempts weremade to remove the paper from the adhesive surface.

Example 21

[0263] A printed film was prepared from 80 μ white coextruded,biaxially-oriented cavitated polypropylene film (BOPP), available asTRESPAPHAN OWD 80 from Hoechst-Trespaphan (Neunkirchen, Germany). Theprintable side of the film had been corona-treated and was printed withan image by flexographic printing. The printed carrier wascorona-treated on both sides.

[0264] A double-coated adhesive sheet was prepared by coating apolymer-containing syrup (90 parts by weight isooctyl acrylate, 10 partsby weight fumed silica (AEROSIL R972 from Degussa) and 0.2 parts byweight photoinitiator (available as IRGACURE 651 from Ciba-Geigy) ontothe printed BOPP film described above. Each of the sides of the BOPPfilm was coated simultaneously via knife coating with two slightlydiffering polymeric syrups, each at a thickness of 100 microns. Thesyrup-coated BOPP was then protected between two siliconizedpolyethylene terephthalate (PET) liners and the adhesive syrups thencured using UV radiation as described in European Patent Application EP0 736 585.

[0265] The syrup used for the printed side of the BOPP contained, inaddition to the isooctyl acrylate and fumed silica components mentionedabove, 2.0% tetrapropylene glycol diacrylate (TPGDA) crosslinking agent.The syrup used for the non-printed side of the BOPP contained 0.5% TPGDAcrosslinking agent. The adhesive layer having the lower amount ofcrosslinker had higher adhesion.

[0266] The printed double-coated adhesive sheet thus prepared wasapplied to an 8 mm thick transparent sheet of polymethylmethacrylate(PMMA) by removing the liner from the adhesive side made with 2.0%crosslinking agent (lower adhesion side) and laminating the adhesive tothe polymethylmethacrylate sheet. The double-coated adhesive applied tothe PMMA formed a clear assembly and the print on the BOPP adhesivecarrier was visible through the PMMA substrate.

[0267] 3M Company No. 8612 Electrostatic paper was coated on the sideopposite the electrostatic coating with a mixture of UV-curablesilicone-release materials. A silicone thickness of about 1 micron wasapplied to the paper and UV cured using high intensity UV lamps. Therelease material employed was a 70:30 weight to weight mixture of twoUV-curable silicones/acrylates: RC 706 and RC 711, available from Th.Goldschmidt AG, Essen, Germany.

[0268] The siliconized image carrier was imaged by electrostaticprinting using the 3M Scotchprint™ imaging process on the side bearingthe coating intended to receive such an image.

[0269] The image carrier was applied to the exposed adhesive layerdescribed above, so that in the final construction two images werevisible: one through the transparent substrate and present on thesubstrate side of the adhesive carrier and a second one applied to theexposed surface of the image carrier.

Example 22

[0270] A 32 micron clear, corona-treated biaxially-orientedpolypropylene (BOPP) (available as Propafilm LMO 30 from ICI) ishot-melt coated with a 50 micron layer of rubber/resin basedpressure-sensitive adhesive comprising 33 parts by weight syntheticrubber (available as CARIFLEX TR 1107 from Shell), 44 parts hydrocarbonresin (Escorez 1310 from Exxon Chemicals) and 22 parts polyterpene resin(available as Zonarez A25 from Arizona Chemicals).

[0271] The other side of the BOPP film is coated in the same manner witha 50 micron layer of rubber/resin based pressure-sensitive adhesiveavailable as Durotak H1525 from National Starch.

[0272] The adhesive side of the double-coated adhesive sheet coated withthe National Starch pressure-sensitive adhesive was then applied to thesurface of a melamine-coated chipboard.

[0273] The image carrier of Example 18, a silicone-coated paper,available as 75 g Release PMC MR30 (high release system) from LohjanPaperi (Finland), was flexographically printed on the non-siliconizedside and used as an image graphic.

Example 23

[0274] In Example 23, the adhesive carrier 12 consisted of a single 25micron layer of pressure-sensitive adhesive in the form of AcrylicTransfer Tape 9458 available from 3M. No polymeric film was present. Thetransfer adhesive was applied to the substrate, in this example amelamine-coated chipboard.

[0275] The image carrier of Example 18, a silicone-coated paper, wasimaged using offset printing and adhered to the exposed surface of thetransfer sheet.

[0276] The image graphic could be removed cleanly and the double-coatedadhesive remained adhered to the substrate.

Example 24

[0277] The clear double-coated adhesive employed in Example 14 wasadhered to a polymethylmethacrylate (PMMA) substrate. The lower adhesionside was adhered to the substrate.

[0278] An image graphic was prepared from a 70 micron white,biaxially-oriented polypropylene (BOPP) film available as Lithor 70LX002from Mobil Plastics, coated on one side with a mixture of two 100%solids UV-curable silicone/acrylate-based release materials, made bycombining 50 parts by weight RC 708 from Th. Goldschmidt AG (Essen,Germany) and 50 parts by weight RC 711 from Th. Goldschmidt AG. Themixture of release materials was coated onto the BOPP using a 5-rollcoating station to provide a coating of about 1 micron. The releasematerial was then UV cured in an inert atmosphere by passing under highintensity mercury UV lamps to cure.

[0279] The non-siliconized surface of the film-based image carrier wasthen printed using flexographic printing. TABLE 3 EasyApplication/Environment SHEET PSA PSA (adhered to IMAGE (adhered toimage GRAPHIC Ex. SUBSTRATE substrate) Carrier graphic) Coating SheetImage 14 Painted metal acrylic polyester acrylic silicone paperhand-written 15 Painted metal acrylic polyester acrylic silicone paperphotocopy 16 Painted metal acrylic polyester acrylic silicone paperlaser print 17 Painted metal acrylic polyester acrylic silicone paperoffset printing C3 ″ acrylic polyester acrylic silicone paper offsetprinting 18 ″ acrylic polyester acrylic silicone paper screen printing19 ″ acrylic polyester acrylic silicone paper ink jet printing 20 PVCfoam board acrylic PVC acrylic PE paper offset printing C4 PVC foamboard acrylic PVC acrylic None paper offset printing C5 PVC foam boardacrylic polyester acrylic PE paper offset printing 21 glass acrylic BOPPacrylic silicone paper electrostatic printed printing 22 melamine coatedrubber BOPP rubber silicone paper flexographic chipboard printing 23melamine coated acrylic double-coated silicone paper offset chipboardadhesive sheet printing 24 PMMA acrylic polyester acrylic silicone filmflexographic printing

[0280] TABLE 4 90° Peel 90° Peel adhesion adhesion 180° Peel 180° PeelDouble-coated Double-coated adhesion adhesion adhesive sheet adhesivesheet Image graphic Image Graphic from substrate from substrate from PSAfrom PSA (N/2.54 cm, (N/2.54 cm, (N/2.54 cm, (N/2.54 cm, Ex. 24 h dwell)14 d dwell) 24 h dwell) 14 d dwell) 14 0.78 1.23 0.03 0.07 15 0.78 1.230.03 0.07 16 0.78 1.23 0.03 0.07 17 0.78 1.23 0.03 0.07 C3 9.47 11.23 falls off falls off 18 0.78 1.23 0.12 0.74 19 0.78 1.23 0.26 0.33 205.76 6.28 4.75 5.29 C4 5.76 6.28 Paper Split Paper Split C5 1.47 1.8914.34  19.83  21 8.43 9.14 0.10 0.12 22 12.15  14.01   0.334  0.291 237.56 8.1  0.12 0.74 24 0.85 0.71  0.076  0.285

Example 25

[0281] An 25 micron thick acrylic double-coated transfer adhesive sheet,available as #9458 Transfer Tape from 3M Company, was laminated to oneside of an 8 mm thick, rigid signboard made of foamed polyvinyl chloridewith a slightly textured surface, commercially available as Forex™ fromAirex AG (Sins, Switzerland).

[0282] A co-extruded film comprising a polyethylene base layer and anethylene vinyl acetate (EVA) print receptor layer was prepared accordingto the disclosure of U.S. Pat. No. 5,721,086 (Emslander et al.) Thecoextruded film was then coated with an adhesion modifying siliconecoating on the side opposite the print receptor layer. The printreceptive layer was then imaged by four-color offset printing.

[0283] The image graphic was then laminated with the siliconized side ofthe image facing the acrylic transfer sheet. The film-based imagegraphic was easily removable from the transfer adhesive and was notdistorted or torn during the removal process, so as to render itreusable. The transfer adhesive was not removable from the substratewithout special methods. The transfer adhesive sheet was removable fromthe substrate, however, if it was covered with a strong paper and peeledoff together with this paper.

[0284] The peel adhesion of the adhesive carrier from the substrate wasevaluated quantitatively by the 90° peel adhesion test (performedaccording to the method described under Test Methods, above) and thepeel adhesion of the image graphic from the adhesive carrier wasevaluated quantitatively by the 180° peel adhesion test (performedaccording to the method described under Test Methods, above).

Example 26

[0285] A 50 micron thick acrylic transfer adhesive sheet, available asProduct No. #966 from 3M Company was laminated to one side of an 8 mmthick, rigid signboard made of foamed polyvinyl chloride with a slightlytextured surface, commercially available as Forex™ from Airex AG (Sins,Switzerland). The image graphic comprised a transparentbiaxially-oriented polypropylene (BOPP) film coated with a thin layer ofpolyurethane-based material, available as KALLE K from Kalle AG(Frankfurt, Germany).

[0286] The image graphic, handwritten, was removable from the transferadhesive sheet. The transfer adhesive sheet was adhered strongly to thesubstrate, but could be removed by bonding another tape to it such as amasking tape.

Example 27

[0287] A 25 micron thick acrylic transfer adhesive sheet, available asTape No. #9458 from 3M Company was laminated to one side of an 8 mmthick, rigid signboard made of foamed polyvinyl chloride with a slightlytextured surface, commercially available as Forex™ from Airex AG (Sins,Switzerland).

[0288] A 70μ white cavitated, coextruded biaxially-orientedpolypropylene (BOPP) film, available as Lithor 70LX002 from MobilPlastics, was coated on one side with radiation curablesilicone-acrylate surface coating comprising a 70:30 (parts by weight)mixture of two silicone-acrylate materials available as RC 706 and RC711, respectively, from Th. Goldschmidt AG (Essen, Germany). The coatingwas applied at a thickness of about 1 micron using a five-roll coatingstation and then UV cured on the film in an inert gas atmosphere usinghigh intensity UV lamps as prescribed by the manufacturers.

[0289] The coated BOPP was then printed on the non-coated side byflexographic printing. The coated side of the image graphic was thenapplied to the exposed surface of the transfer sheet.

[0290] The image graphic was removable from the adhesive surface withoutstretching or distorting the BOPP film. The transfer adhesive sheet waspermanently bonded to the substrate

Comparative Example 6

[0291] Example 27 was repeated, with the exception that the surfacemodifier coating was not present on the image graphic. The image graphicwas not cleanly removable from the transfer adhesive surface. Portionsof the transfer adhesive sheet were removed from the surface andremained adhered to the image graphic.

Example 28

[0292] An advertising board comprising a painted steel sheet was chosenas a substrate. A DIN A4 sheet (21 cm×29.7 cm) of double-coated transferadhesive sheet having a high tack acrylic PSA on one side and a low tackacrylic PSA on the other side, available as No. 9415 High Tack/Low TackDouble-Coated Tape from 3M Company, St. Paul, Minn., USA, was laminatedto cover one of the two surfaces of the advertising board. The liner wasremoved from the low adhesion side and then the low adhesion side of thetransfer adhesive sheet was applied to the painted metal surface using arubber-coated roller.

[0293] A white, 115 micron, cast polypropylene film was coated on oneside with radiation curable silicone-acrylate release materialcomprising a 70:30 (parts by weight) mixture of two silicone-acrylatematerials available as RC 706 and RC 711, respectively, from Th.Goldschmidt AG (Essen, Germany). The release coating was applied at athickness of about 1 micron using a five-roll coating station and thenUV cured on the film in an inert gas atmosphere using high intensity UVlamps as prescribed by the manufacturers.

[0294] The silicone-coated polypropylene described above was then imagedon the non-siliconized side by screen printing.

[0295] The image carrier was then adhered to the double-coated adhesiveby contacting the siliconized side of the polypropylene to the highadhesion side of the transfer adhesive sheet. The image graphic wasremovable and was not damaged during the removal process.

Comparative Example 7 Example 28 was repeated with the exception thatthe transfer adhesive sheet was applied to the substrate in the reversemanner, that is, where the high adhesion side was adhered to thesubstrate.

[0296] The image carrier of Example 28 was then adhered to the exposedsurface of the transfer adhesive sheet.

[0297] The adhesion between the exposed adhesive layer and the imagegraphic was insufficient to hold the image graphic to the surface and itfell off without application of external peel forces.

Example 29

[0298] A double-coated adhesive sheet was prepared by laminating anacrylic transfer sheet, No. 9470 available from 3M, to both sides of a36 micron clear polyester, available as Hostaphan RN 36 from Hoechst(Frankfurt, Germany). The transfer adhesive sheet thus prepared was thenadhered to melamine-coated chipboard.

[0299] An image carrier was prepared from a paper having high wetstrength, available as Scotchprint™ 8618 Electrostatic Paper from 3MCompany. The paper was silicone-coated (on the side opposite thatintended for the electrostatic image) with the UV curable siliconemixture of Example 27.

[0300] The image carrier was provided with an image using electrostaticprinting. Then the siliconized side of the image graphic was applied tothe double-coated adhesive sheet. The image graphic was removablewithout tearing the paper.

Example 30

[0301] A 50 micron white polyester, available as Mylar XMWH 12 fromDuPont, was printed on one side using offset printing. A 50 micron thickacrylic transfer sheet, available as Transfer Tape No. 966 from 3MCompany, was then laminated to the printed side of the polyester. Theother side of the polyester was laminated to a second 50 micron thickacrylic transfer sheet, available as No. 9470 Transfer Tape from 3MCompany, to make a double-coated adhesive sheet.

[0302] The double-coated adhesive sheet was then adhered to 8 mm thickpolymethylmethacrylate (PMMA) panel, using the less adhesive sidecomprising transfer sheet No. 966.

[0303] The image carrier of Example 28 (cast PP with UV-curedsilicone/acrylate release coating) was imaged using offset printing andadhered to the exposed adhesive of the double-coated adhesive sheet.

[0304] In these examples, a first image present on the substrate side ofthe adhesive carrier could be viewed through the substrate and a secondimage could be viewed from on the exposed surface of the image carrier.TABLE 5 Easy Application/Challenging Environment SHEET PSA PSA (adheredto IMAGE (adhered to image GRAPHIC Ex. SUBSTRATE substrate) Carriergraphic) Coating Sheet Image 25 PVC foam board acrylic double-coatedsheet silicone 3M film offset printing 26 PVC foam board acrylicdouble-coated sheet Poly- BOPP hand-writing urethane 27 PVC foam boardacrylic double-coated sheet silicone BOPP Flexographic printing C6 PVCfoam board acrylic double-coated sheet none BOPP Flexographic printing28 Painted metal acrylic polyester Acrylic silicone cast PP screenprinting C7 Painted metal acrylic polyester Acrylic silicone cast PPscreen printing 29 melamine coated acrylic polyester Acrylic siliconePaper (with electrostatic chipboard wet strength) printing 30 PMMAacrylic polyester Acrylic silicone cast PP offset (printed) printing

[0305] TABLE 6 90° Peel 90° Peel adhesion adhesion 180° Peel 180° PeelDouble-coated Double-coated adhesion adhesion adhesive sheet adhesivesheet Image graphic Image Graphic from substrate from substrate from PSAfrom PSA (N/2.54 cm, (N/2.54 cm, (N/2.54 cm, (N/2.54 cm, Ex. 24 h dwell)14 d dwell) 24 h dwell) 14 d dwell) 25 7.48 11.82 0.43 2.36 26 3.0811.15  0.642 0.75 27 7.48 11.82 0.55 1.68 C6 7.48 11.82 8.89 11.64  280.78  1.23  0.214 0.13 C7 9.47 11.23 falls off falls off 29 13.7  16.47 0.321 0.19 30 8.87 13.25  0.321 0.19

Example 31

[0306] A double-coated adhesive sheet was prepared by first coating ahigher adhesion solvent-based acrylic pressure-sensitive adhesive,available as AROSET #1450 from Ashland Chemical (Columbus, Ohio, USA)onto a 36 micron polyethylene terephthalate (PET) film (both sidescorona treated, available as Hostaphan RN 36 from Hoechst AG) andcovering the dried adhesive layer with a siliconized paper liner. Theopposite side of the polyethylene terephthalate film was coated in asimilar manner with a layer of a second, lower adhesion solvent-basedacrylic pressure-sensitive available as AROSET #1452 from AshlandChemical (Columbus, Ohio, USA). The second adhesive layer was alsoprotected with a siliconized paper liner.

[0307] The liner was removed from the higher adhesion side and then a 21cm×27.9 cm (DIN A4) sheet thus prepared was laminated to Forex™ board(available from Airex AG, Sins, Switzerland) with the higher adhesionside of the double-coated adhesive sheet towards the substrate.

[0308] An image graphic was prepared by printing a 60μ thick, white,printable, coextruded, cavitated, biaxially-oriented polypropylene(BOPP), available as LABELYTE 60 LH 534 from Mobil Plastics, usingoffset printing. The image graphic was laminated to the double-coatedadhesive sheet in DIN A 4 size after removal of the liner.

[0309] The image carrier adhered securely to the adhesive surface, butwas easily removable. The double-coated adhesive sheet did not lift fromthe substrate during removal of the image graphic.

[0310] The peel adhesion of the adhesive carrier from the substrate andthe peel adhesion of the image graphic from the adhesive carrier wereevaluated quantitatively by the 90° peel adhesion test (performedaccording to the method described under Test Methods, above).

[0311] After the image graphic was removed, the exposed adhesive surfacewas deliberately contaminated with particulate manner consisting of amixture of 38.4% by weight peat, 18.0% by weight cement, 18.0% kaolinand 18.0% diatomaceous earth, 6.25% mineral oil and 1.05% carbon blackand 0.3% ferrous oxide. One gram of the above mixture was sprinkledevenly onto an adhesive sheet measuring 15 cm×15 cm. The contaminatedsurface was then washed with a dilute aqueous soap solution, rinsed andallowed to dry. Adhesion values of the cleaned adhesive surface hadreturned to 80% of the uncontaminated value.

Comparative Example 8

[0312] Example 31 was repeated with the exception that double-coatedadhesive sheet was adhered to the substrate in reverse fashion, that is,where the lower adhesion side was towards the substrate.

[0313] The image graphic of Example 31 was applied to the exposedsurface of the sheet. The image graphic was not removable from thesheet. On attempts to remove the image graphic, the entire assembly,including the double-coated adhesive sheet, separated from thesubstrate.

Comparative Example 9

[0314] Example 31 was repeated with the exception that another imagegraphic was employed. The image graphic was an embossed castpolypropylene film. Because of the embossing, the contact between theimage carrier and the adhesive surface was insufficient to make a goodadhesive bond, the image carrier separated from the adhesive surface dueto its own weight without application of external peel forces when theassembly placed in a vertical position.

Example 32

[0315] A double-coated adhesive sheet was prepared by coating a 36 μclear polyethylene terepthalate (PET), available as Hostaphan RN 36 fromHoechst (both sides corona treated), with a mixture of two solvent-basedacrylic pressure-sensitive adhesives. The adhesive mixture consisted ofone part by weight of a lower adhesion solvent-based acrylicpressure-sensitive, available as AROSET #1452 from Ashland, and 3 partsby weight of a second higher adhesion acrylic pressure-sensitiveadhesive, available as AROSET #1450 from Ashland Chemical (Michigan,USA). This mixture was coated on the one side of the sheet to form thehigher adhesion side of the sheet to give a dry coating weight of 50microns. A mixture of 3 parts AROSET 1452 (described above) and one partAROSET 1450 (described above) was coated on the other side of the sheet,also at a dry coating weight of 50 microns, to form the lower adhesionside of the double-coated adhesive sheet.

[0316] The double-coated adhesive sheet thus prepared was adhered to thesubstrate with the higher adhesion side facing the substrate.

[0317] The image graphic was prepared by screen printing one side of asheet of 115 micron thick, white, extruded non-oriented polypropylenefilm, extruded from a mixture of 91% by weight pellets of polypropylene(available as Finapro 7060S from Fina Chemicals) and 9% by weightpellets of polyethylene containing titanium dioxide pigment (availableas REMAFIN weiss from Hoechst). The image graphic was applied to the lowadhesion side of the double-coated adhesive sheet. The image graphic wasremovable from the adhesive surface without distorting or damaging it.The double-coated adhesive sheet did not lift from the substrate duringremoval of the graphic. The double-coated adhesive sheet itself was alsoremovable from the substrate.

Example 33

[0318] A 80 micron white biaxially-oriented polypropylene (BOPP)available as Trespaphan OWD 80 from Hoechst-Trespaphan (Neunkirchen,Germany) was printed on one side with an image using flexographicprinting. A clear double-coated adhesive sheet was then prepared bycoating a acrylate-based low viscosity syrup (90 parts by weightisooctyl acrylate, 10 parts by weight fumed silica (AEROSIL R972 fromDegussa and 0.2 parts by weight photoinitiator (available as IRGACURE651 from Ciba-Geigy) onto the printed BOPP described above. Each of thesides of the BOPP carrier was coated simultaneously via knife coatingwith two slightly differing syrups comprising a mixture of acrylicpolymer and monomer, each at a thickness of 100 microns.

[0319] The syrup used for one side contained, in addition to thecomponents mentioned above, 2.0% tetrapropyleneglycol diacrylate (TPGDA)crosslinking agent. The syrup used for the other side contained 0.5%TPGDA crosslinking agent. The adhesive layer having the lower amount ofcrosslinker had higher adhesion. The syrup containing the lesser amountof crosslinker (0.5%) was coated onto the side of the BOPP film bearingthe printed image. The syrup-coated BOPP was then protected between twosiliconized polyethylene terephthalate (PET) liners and the syrups thencured using UV radiation as described in European Patent Application EP0 736 585 to make pressure-sensitive adhesive layers.

[0320] The double-coated adhesive sheet thus prepared was adhered to aglass plate with the side of the double-coated adhesive sheet bearingthe adhesive with the lesser amount (0.5%) of crosslinker. The lesseramount of crosslinker resulting in a higher adhesion pressure-sensitiveadhesive. The side of the BOPP bearing the printed image also faced theglass substrate.

[0321] The image carrier comprised a 70 micron sheet of white,cavitated, biaxially-oriented polypropylene (BOPP), available as Lithor70LX002 from Mobil Plastics. The film was a coextruded multilayerconstruction with a cavitated BOPP core and a BOPP-based skin layer onat least one side which was specially modified to be print receptive,especially for flexographic applications.

[0322] The film was then imaged on the image-receptive side usingflexographic printing and the non-imaged side applied to the exposedface of the double-coated adhesive sheet. In this example, two imageswere visible: the image on the adhesive carrier was visible through theglass substrate and the image on the image carrier was visible from theopposite side of the completed construction. The image on the adhesivecarrier formed a permanent part of the display, whereas the imagecarrier was removable and replaceable by other image graphics.

Example 34

[0323] A double-coated adhesive sheet was prepared using a 50 micron,white, polyethylene terephthalate (PET) film, available as Mylar XMWH 12from DuPont. The film was corona treated on both sides. The film wasfirst coated with a 75:25 mixture by weight of two solvent-based acrylicpressure-sensitive adhesives: Aroset 1450 from Ashland Chemical andAroset 1452 from Ashland Chemical. The adhesive was coated using aknife-coater and dried in a forced air oven to give a dry coating weightof 50 microns.

[0324] A layer of acrylic pressure-sensitive adhesive as described incopending, coassigned, U.S. patent application Ser. No. 09/118,590 wascoated onto a silicone-coated polyester liner to give a final thicknessof 25 microns. The adhesive layer was then transferred to the secondside of the polyester backing described above.

[0325] The double-coated adhesive sheet thus prepared was adhered to apainted metal sheet commonly used as a surface for outdoor advertisingdisplays. The higher adhesion side of the double-coated adhesive sheet(bearing the solvent-borne mixture of two acrylic PSAs described first)was applied to the painted metal substrate.

[0326] The image carrier was a sheet of 75 micron white polyethyleneterephthalate (PET) available as Mylar XMWH11 from DuPont. The imagecarrier was imaged using offset printing and then the non-imaged surfacewas adhered to the exposed surface of the double-coated adhesive sheet.

[0327] The image carrier was removable from the double-coated adhesivesheet with peel forces described in the table below. The image carrierwas not damaged or distorted during the removal process, nor was thedouble-coated adhesive sheet removed from the substrate.

Example 35

[0328] A 30 micron clear biaxially-oriented polypropylene (BOPP) film,available as Propafilm LMO 30 from ICI was corona-treated on both sides.One side was coated with a higher adhesion solvent-based acrylicpressure-sensitive adhesive, available as AROSET #1450 from AshlandChemical (Columbus, Ohio, USA). The adhesive was then dried in a forcedair oven and covered with a siliconized paper liner. The opposite sideof the BOPP film was coated in a similar manner with a layer of asecond, lower adhesion solvent-based acrylic pressure-sensitiveavailable as AROSET #1452 from Ashland Chemical (Columbus, Ohio, USA).

[0329] The double-coated adhesive sheet thus formed was applied to thepainted metal surface with the higher adhesion side toward thesubstrate. The image carrier was a sheet of flexible retroreflectivesheeting available as Scotchlite™ VP 5500 Reflective Sheeting from 3M.The non-retroreflective surface of the sheeting which contacted thedouble-coated adhesive sheet bore a layer of polyester film. Theretroreflective surface of the sheeting was provided with an image byscreen printing.

[0330] The image carrier was then adhered to exposed adhesive surface ofthe double-coated adhesive sheet. The retroreflective sheeting wasremovable without damaging it or distorting it and the double-coatedadhesive sheet remained on the substrate.

Example 36

[0331] Example 35 was repeated, with the exception that the imagecarrier was a sheet of paper having high wet strength (available asScotchprint™ 8618 from 3M) which was imaged using electrostatic methods.After imaging, the imaged surface of the image carrier was laminated toa transparent sheet bearing a clear adhesive (available as Scotchprint™8910 Lustre Laminate from 3M Company) to enhance the appearance andstability of the image and the image carrier. TABLE 7 ConventionalApplication/Challenging Environment SHEET PSA PSA (adhered to IMAGE(adhered to image GRAPHIC Ex. SUBSTRATE substrate) Carrier graphic)Sheet Image 31 PVC foam board acrylic polyester acrylic BOPP Offsetprinting C8 PVC foam board acrylic polyester acrylic BOPP Offsetprinting C9 PVC foam board acrylic polyester acrylic Cast PP Offsetprinting 32 PVC foam board acrylic polyester acrylic Cast PPScreen-printing 33 Glass acrylic BOPP acrylic BOPP Flexographic printing34 Painted Metal acrylic polyester acrylic polyester Offset printing 35Painted Metal acrylic BOPP acrylic Retroreflective Screen printingsheeting 36 Painted Metal acrylic BOPP acrylic Paper with wetElectrostatic strength Printing

[0332] TABLE 8 90° Peel 90° Peel adhesion adhesion 90° Peel 90° PeelDouble-coated Double-coated adhesion adhesion adhesive sheet adhesivesheet Image graphic Image Graphic from substrate from substrate from PSAfrom PSA (N/2.54 cm, (N/2.54 cm, (N/2.54 cm, (N/2.54 cm, Ex. 24 h dwell)14 d dwell) 24 h dwell) 14 d dwell) 31 7.66 10.48  3.54 4.54 C8 0.481.67 6.34 7.4  C9 7.66 10.48  falls off falls off 32 3.43 4.50 0.76 0.7033 5.19 4.81 0.08 0.45 34 3.43 4.50 1.48 1.95 35 6.01 9.72 3.02 4.45 366.01 9.72 0.53 0.67

Example 37

[0333] An adhesive carrier was prepared using a 21 micron thick primedpolyester. The polyester was coated on one side with an acrylic PSA(A-1266, internal from 3M) to give a nominal dry coating weight of 30grams/square meter. The other side of the polyester film was coated witha methyl ethyl ketone solution of a terpolymer comprising of 35%acrylonitrile, 58% butadiene and 7% isoprene, available as NipolDN-1201L (Zeon Chemical Co.) to give a nominal dry coating weight of 35grams/square meter. The adhesive acrylic PSA layer was protected with asilicone paper release liner.

[0334] The laminate just described was then bonded to an aluminum 6061(30.4 cm×6.9 cm) test panel using the acrylic adhesive side. A 2.54cm×17.78 cm sheet of extruded 0.1 mm plasticized polyvinylchloride wasbonded by hand to the exposed surface ofacrylonitrile-butadiene-isoprene terpolymer using a squeegee such that6.9 cm of the vinyl strip was bonded to the terpolymer surface and theremainder was hanging free from the panel.

[0335] The film sample was then tested via a 180° peel test at varioustime intervals and various conditions of aging on a tensile tester at arate of 30 mm per minute. Each test was replicated three times and amean value was calculated.

Example 38

[0336] Example 37 was repeated with the exception that the plasticizedPVC image carrier was coated with a 50% solids acrylate modifiedethylene vinyl acetate terpolymer emulsion (available as Airflex 120from Air Products Co., Allentown, Pa.), at 0.075 mm wet coating weightand dried at 10 min at 65° C. results in a coating weight of about least6 grains per 154 cm² (24 in²).

Example 39

[0337] Example 37 was repeated with the exception that the plasticizedPVC image carrier was coated with a 50% solids vinyl acetate homopolymeremulsion (available as Gelva TS85 from Monsanto Co., St. Louis. Mo.), atthe conditions of Example 38.

Example 40

[0338] Example 37 was repeated with the exception that the plasticizedPVC image carrier was coated with a 50% solids ethylene vinyl acetatecopolymer (available as Gelva TS-100 from Monsanto Co., St. Louis. Mo.),at the conditions of Example 38.

[0339] Table 9 shows the results. TABLE 9 180° Peel Adhesion, 180° PeelAdhesion, 180° Peel Adhesion, Example initial (N/m) 24 h at 23° C. (N/m)7 d at 65° C. (N/m) 37 591 1061  1583  38 121 243 887 39C delaminatesDelaminates Delaminates 40 417 626 643

Example 41

[0340] The double-coated adhesive sheet of Example 37 was employed asadhesive and a polyethylene terephthalate film (PET) employed as theimage carrier.

Examples 42-44

[0341] Example 41 was repeated with the exception that the image carrierwas a PET film which had been vapor-coated with metal on one side. Themetals employed were nickel, silver and indium-tin oxide, respectively.The vapor-coated side of the film was adhered to the exposed surface ofthe double-coated adhesive sheet of Example 37 bearing the layer ofacrylonitrile-butadiene-isoprene terpolymer. Table 10 shows the testresults. TABLE 10 180° Peel Adhesion, 180° Peel Adhesion, 180° PeelAdhesion, Example initial (N/m) 24 h at 23° C. (N/m) 7 d at 65° C. (N/m)41 382 626 643 42 156 121 156 43 34.8 208 1409 44 0 34.8 6.9

Examples 45-46

[0342] The double-coated adhesive sheet of Example 37 was employed as anadhesive carrier and impact modified polypropylene (available as SRD7-587 from Union Carbide, Danbury, Conn.) was used as the image carrier.The PP film was evaluated in both non corona-treated and corona-treatedforms, respectively. When corona-treatment was present, the treated sidewas adhered to the exposed terpolymer surface of the double-coatedadhesive sheet.

Examples 47-48

[0343] The double-coated adhesive sheet of Example 37 was employed as anadhesive carrier and a sheet of polyethylene-co-acrylic acid (availableas Primacor 1430 from Dow Chemical Co., Midland, Mich., USA.), was usedas the image carrier. The E-AA copolymer film was evaluated in both noncorona-treated and corona-treated forms, respectively. Whencorona-treatment was present, the treated side was adhered to theexposed terpolymer surface of the double-coated adhesive sheet.

Examples 49-50

[0344] The double-coated adhesive sheet of Example 37 was employed as anadhesive carrier and an ionomeric film (available as Surlyn 1705 fromDuPont Co., Wilmington, Del.) was used as the image carrier. The filmwas evaluated in both non corona-treated and corona-treated forms,respectively. When corona-treatment was present, the treated side wasadhered to the exposed terpolymer surface of the double-coated adhesivesheet.

Examples 51-52

[0345] The double-coated adhesive sheet of Example 37 was employed as anadhesive carrier and a sheet of low density polyethylene (available asExxon 108.37, from Exxon Chemical Co.), was used as the image carrier.The LDPE film was evaluated in both non corona-treated andcorona-treated forms, respectively. When corona-treatment was present,the treated side was adhered to the exposed terpolymer surface of thedouble-coated adhesive sheet.

Examples 53-54

[0346] The double-coated adhesive sheet of Example 37 was employed as anadhesive carrier and a sheet of high density polyethylene (available as9640 from Chevron) was used as the image carrier. The HDPE film wasevaluated in both non corona-treated and corona-treated forms,respectively. When corona-treatment was present, the treated side wasadhered to the exposed terpolymer surface of the double-coated adhesivesheet.

[0347] Table 11 shows the test results. TABLE 11 180° Peel 180° Peel180° Peel 180° Peel 180° Peel Adhesion, Adhesion, Adhesion, Adhesion,Adhesion, 24 h at 7 d at 28 d at 7 d at initial 23° C. 23° C. 23° C. 65°C. Example (N/m) (N/m) (N/m) (N/m) (N/m) 45 52 122 174 278 261 46 139296 348 522 783 47 017.4 17.4  35  35 104 48 139 278 278 348 957 49 3552  52  52 313 50 174 487 226 209 1409  51 52 69 104  70 557 52 104 121226 244 1322  53 35 52  87  70 122 54 156 539 296 313 1253 

Example 55

[0348] The double coated sheet of Example 37 was employed as adhesivecarrier and was bonded to a 30.48 cm by 30.48 cm painted aluminum panelsubstrate. The surface consisting of acrylonitrile-butadiene-isopreneterpolymer was exposed and the acrylic PSA bonded to the substrate.

[0349] A three layer film consisting of a thicker core layer of lowdensity polyethylene, a first thinner skin layer of ethylene vinylacetate copolymer and a second thinner skin layer of acrylate-modifiedethylene vinyl acetate copolymer was extruded simultaneously and formedthe image carrier. Both surface layers were corona treated. An image wasprinted on the surface consisting of the acrylate-modified EVA using theScotchprint™ hot roll image transfer process on an Orca III Laminator.

[0350] The non-imaged ethylene vinyl acetate copolymer surface of thethree-layer image carrier was bonded to the exposed surface of theacrylonitrile-butadiene-isoprene terpolymer.

Example 56

[0351] Example 55 was repeated with the exception that the EVA layer ofthe three layer image carrier was not corona treated before bonding tothe exposed acrylonitrile terpolymer face of the double-coated adhesivesheet.

[0352] Table 12 shows the test results. TABLE 12 180° Peel 180° PeelAdhesion, 180° Peel Adhesion, Adhesion, 7 days Example initial (N/m) 24h at 23° C. (lb/in) at 65° C. (N/m) 55 104 208 1409 56 139 121  226

Example 57

[0353] Example 55 was repeated with the exception that 1) the film usedfor the adhesive carrier was a clear polyethylene terephthalate film and2) the adhesive carrier was bonded to a glass plate using the acrylicPSA.

[0354] The image graphic was prepared in the same manner as in Example55, except that after printing, a clear overlaminate film consisting ofa clear low density polyethylene with a clear acrylic PSA was bonded tothe graphic by means of the clear acrylic PSA. The resulting protectedgraphic was bonded by adhering the imaged side to the exposed layer ofacrylonitrile-butadiene-isoprene terpolymer. The graphic could clearlybe seen through the glass and the clear double-coated adhesive sheet.

[0355] The graphic could be removed cleanly with out damage to thegraphic or to the adhesive layer, such that both components can bereused.

Example 58

[0356] A three layer film was prepared by coextrusion for use as animage carrier. The core was a linear low density polyethylene (availableas Chevron 6109T from Chevron Chemical). The two outer skin layersconsisted of acrylate-modified ethylene vinyl acetate copolymer(available as Bynel 3101 from DuPont) and low density polyethylene(available as Exxon 108.37 from Exxon Chemical). The total caliper ofthe 3-layer film was 0.2 mm, with the majority of the total thicknessbeing made up of the core layer. The film was printed in the same manneras in Example 55.

[0357] The imaged carrier was used in conjunction with the double-coatedadhesive sheet of Example 37 as described in Example 37. Despite thethick caliper of the film, the adhesive force was sufficient to preventlifting or curling of the graphic during use.

Example 59

[0358] A first layer of pressure-sensitive adhesive was prepared by 1)preparing a viscous syrup by partially UV polymerizing 100 parts byweight isooctylacrylate, 0.04 parts photoinitiator available as Irgacure651 from Ciba Chemical Specialties. To the syrup were added 0.2 partshexanediol diacrylate and an additional 0.15 parts Irgacure 651photoinitiator. The syrup was applied with a knife coater between twosilicone-coated polyester liners and polymerized using medium pressureUV lamps. The adhesive layer was exposed to a total of 7.4milliwatts/cm² (NIST units). The thickness of the adhesive layer thusprepared was 60 microns.

[0359] One of the liners was removed and the adhesive layer laminated toa transparent corona-treated (both sides) polyethylene terephthalatefilm (PET) having a thickness of 50 microns.

[0360] The opposite side of the polyester film was coated with a solventborne acrylic pressure-sensitive adhesive available as AEROSET 1450-Z-40from Ashland Chemical (Columbus, Ohio, USA). The adhesive was appliedwith a knife-coater and dried in a forced air oven for 30 seconds at120° C. The final thickness of the second adhesive layer was 30 microns.

[0361] An image graphic was then prepared by first printing a four colorimage by offset printing on a 120 g paper.

[0362] The non-printed side of the image graphic was then adhered to thepressure-sensitive adhesive coating of an adhesive sheet comprising abiaxially-oriented polypropylene (BOPP) backing and a rubber resin-basedpressure-sensitive adhesive, available as Packaging Tape Number PP-230from 3M, St. Paul, Minn.

[0363] For the first application to the substrate, the entire imagegraphic was laminated to the double-coated adhesive sheet just describedwith the first adhesive side (described above as isooctylacrylate side)towards the image graphic and the second exposed adhesive side(described above as the solvent borne acrylic side) temporarilyprotected by a liner. The image graphic (comprising the printed paperand packaging sheet)/double-coated adhesive sheet/liner laminate wasthen cut into sections corresponding to the size of a single face of therotating sign components. The liner was then removed and each of thesections thus prepared was adhered to one of the three faces of a seriesof independently rotating triangular aluminum components of a billboardsystem available as Triple Wave Display from World Sign InternationalAB, Sollentuna, Sweden, in such a manner that the entire image graphicwas presented in its entire form, distributed across the rotatingparallel panels.

[0364] After seven days of outdoor application the image graphic wasremoved. The double-coated adhesive sheet remained on the aluminumsurface. A second image graphic, differing only in image from the first,was then cut into sections and applied to the double-coated adhesivesheet which remained on the surface of the sign panel.

[0365] After repeated use, the double-coated adhesive sheet could alsobe cleanly removed from the aluminum sign panel surface.

[0366] The invention is not limited to the above embodiments.

What is claimed is:
 1. A method of displaying an image using a reusableadhesive surface, comprising the steps of: (a) providing a flexibleadhesive carrier having first and second major surfaces, each surfacebeing substantially covered by an adhesive, the first adhesive surfaceengineered to bond the adhesive carrier to a substrate and the secondadhesive surface engineered to releasably secure an image carrier to theadhesive carrier; (b) bonding the adhesive carrier to a substrate at thefirst surface; (c) providing a first flexible image carrier having firstand second major surfaces, the first surface being imageable and thesecond surface being adapted to contact the releasably securing adhesivesurface of the adhesive carrier, wherein the image carrier is notadapted to adhere to the substrate; (d) imaging the first image carrieron the first surface; and (e) removably adhering the first image carrierto the adhesive carrier by contacting the second surface of the firstimage carrier with the second surface of the adhesive carrier, andallowing said first image carrier to reside on said adhesive carrier fora predetermined period of time; wherein the image carrier and theadhesive carrier are substantially coextensive in size.
 2. A methodaccording to claim 1 for displaying multiple images at the same locationin a serial manner using a reusable adhesive surface, further comprisingthe steps of: (f) providing a second flexible image carrier having firstand second major surfaces, the first surface being imageable and thesecond surface being adapted to contact the releasably securing adhesivesurface of the adhesive carrier, wherein the second image carrier is notadapted to adhere to the substrate; (g) imaging the second image carrieron the first surface; (h) removing the first image carrier from theadhesive carrier; and (i) removably adhering the second image carrier tothe adhesive carrier by contacting the second surface of the secondimage carrier with the second surface of the adhesive carrier, andallowing said second image carrier to reside on said adhesive carrierfor a predetermined period of time; wherein the image carriers and theadhesive carrier are substantially coextensive in size.
 3. A method ofdisplaying an image using a reusable adhesive surface, comprising thesteps of: (a) providing an adhesively mountable image graphic compositehaving a reusable adhesive surface, comprising: (i) a flexible adhesivecarrier having first and second major surfaces, each surface beingsubstantially covered by an adhesive, the first adhesive surfaceengineered to bond the adhesive carrier to a substrate and the secondadhesive surface engineered to releasably secure an image carrier to theadhesive carrier; and (ii) a flexible image carrier having first andsecond major surfaces, the first surface being imageable and the secondsurface being in releasable contact with the releasably securingadhesive surface of the adhesive carrier; wherein the image carrier andthe adhesive carrier are substantially coextensive in size; (b) imagingthe image carrier on the first surface of the image carrier; and (c)bonding the adhesive carrier to a substrate at the first surface of theadhesive carrier.
 4. A method according to claim 3 for displayingmultiple images at the same location in a serial manner using a reusableadhesive surface, further comprising the steps of: (d) providing asecond flexible image carrier having first and second major surfaces,the first surface being imageable and the second surface being adaptedto contact the releasably securing adhesive surface of the adhesivecarrier, wherein the second image carrier is not adapted to adhere tothe substrate; (e) imaging the second image carrier on the firstsurface; (f) removing the first image carrier from the adhesive carrier;and (g) removably adhering the second image carrier to the adhesivecarrier by contacting the second surface of the second image carrierwith the second surface of the adhesive carrier, and allowing saidsecond image carrier to reside on said adhesive carrier for apredetermined period of time; wherein the image carriers and theadhesive carrier are substantially coextensive in size.
 5. A method ofdisplaying an image using a reusable adhesive surface, comprising thesteps of: (a) providing a transparent or translucent, flexible adhesivecarrier having first and second major surfaces, each surface beingsubstantially covered by an adhesive, the first adhesive surfaceengineered to bond the adhesive carrier to a substrate and the secondadhesive surface engineered to releasably secure an image carrier to theadhesive carrier; (b) bonding the adhesive carrier to a transparent ortranslucent substrate at the first surface; (c) providing a flexibleimage carrier having first and second major surfaces, the first surfacebeing imageable and further being adapted to contact the releasablysecuring adhesive surface of the adhesive carrier, wherein the imagecarrier is not adapted to adhere to the substrate; (d) imaging the imagecarrier on the first surface such that the image does not transfer tothe adhesive carrier upon removal from the adhesive carrier; (e)removably adhering the image carrier to the adhesive carrier bycontacting the first surface of the image carrier with the secondsurface of the adhesive carrier, and allowing said image carrier toreside on said adhesive carrier for a predetermined period of time;wherein the image carrier and the adhesive carrier are substantiallycoextensive in size.
 6. A method according to claim 5 for displayingmultiple images at the same location in a serial manner using a reusableadhesive surface, further comprising the steps of: (f) providing asecond flexible image carrier having first and second major surfaces,the first surface being imageable and further being adapted to contactthe releasably securing adhesive surface of the adhesive carrier,wherein the second image carrier is not adapted to adhere to thesubstrate; (g) imaging the second image carrier on the first surface;(h) removing the first image carrier from the adhesive carrier withouttransfer of the image to the adhesive carrier; and (i) removablyadhering the second image carrier to the adhesive carrier by contactingthe second surface of the second image carrier with the second surfaceof the adhesive carrier, and allowing said second image carrier toreside on said adhesive carrier for a predetermined period of time;wherein the image carriers and the adhesive carrier are substantiallycoextensive in size.
 7. The method of claim 1, wherein the adhesivecarrier is removable from the substrate without tearing of the adhesivecarrier.
 8. The method of claim 1, wherein the image carrier may beremoved and reapplied to the adhesive carrier without distortion ordamage to the image.
 9. The method of claim 2, wherein steps (c) and (f)are carried out at substantially the same time.
 10. The method of claim2, wherein steps (d) and (g) are carried out at substantially the sametime.
 11. The method of claim 1, wherein the adhesive on the secondadhesive surface is washable.
 12. The method of claim 1, wherein thesubstrate is a front panel of a backlit light display.
 13. The method ofclaim 1, wherein the image carrier is imaged using a method selectedfrom the group consisting of thermal transfer of colorant, inkjetprinting, screen printing, offset printing, flexographic printing, laserprinting, electrophotographic printing, electrostatic transfer printing,and combinations thereof.
 14. The method of claim 1, wherein thesubstrate is a multiple face, multiple component, rotating billboardsystem.
 15. The method of claim 1, wherein the adhesive carrier and theimage carrier are individually transparent or translucent, such thatthey are suitable for use for attachment to the front panel of a backlitlight display.
 16. The method of claim 5, wherein the image carrier isadditionally imaged on the second surface of the image carrier.
 17. Akit for displaying an image using a reusable adhesive surface,comprising: (a) a flexible adhesive carrier having first and secondmajor surfaces, each surface being substantially covered by an adhesive,the first adhesive surface engineered to bond the adhesive carrier to asubstrate and the second adhesive surface engineered to releasablysecure an image carrier to the adhesive carrier; (b) a flexible imagecarrier having first and second major surfaces, the first surface beingimageable and the second surface being adapted to contact the releasablysecuring adhesive surface of the adhesive carrier, wherein the imagecarrier is not adapted to adhere to the substrate; wherein the imagecarrier and the adhesive carrier are substantially coextensive in size.18. The kit of claim 17, wherein the adhesive carrier is capable ofbeing removed from the substrate without tearing of the adhesivecarrier.
 19. The kit of claim 17, wherein the image carrier is capableof being removed and reapplied without distortion or damage to theimage.
 20. The kit of claim 17, wherein the adhesive on the secondadhesive surface is washable.
 21. The kit of claim 17, wherein theadhesive carrier and the image carrier are individually transparent ortranslucent, such that they are suitable for use for attachment to thefront panel of a backlit light display.
 22. The kit of claim 17, whereinthe image carrier is capable of being imaged using a method selectedfrom the group consisting of thermal transfer of colorant, inkjetprinting, screen printing, offset printing, flexographic printing, laserprinting, electrophotographic printing, electrostatic transfer printing,and combinations thereof.
 23. A kit for displaying an image using areusable adhesive surface, comprising: (a) a flexible adhesive carrierhaving first and second major surfaces, each surface being substantiallycovered by an adhesive, the first adhesive surface engineered to bondthe adhesive carrier to a substrate and the second adhesive surfaceengineered to releasably secure an image carrier to the adhesivecarrier; (b) a flexible image carrier having first and second majorsurfaces, the first surface being imaged and the second surface beingadapted to contact the releasably securing adhesive surface of theadhesive carrier, wherein the image carrier is not adapted to adhere tothe substrate; wherein the image carrier and the adhesive carrier aresubstantially coextensive in size.
 24. A kit for displaying an imageusing a reusable adhesive surface, comprising: (a) a transparent ortranslucent flexible adhesive carrier having first and second majorsurfaces, each surface being substantially covered by an adhesive, thefirst adhesive surface engineered to bond the adhesive carrier to asubstrate and the second adhesive surface engineered to releasablysecure an image carrier to the adhesive carrier; (b) a flexible imagecarrier having first and second major surfaces, the first surface beingimaged such that the image does not transfer to the adhesive carrierupon removal from the adhesive carrier, and being adapted to contact thereleasably securing adhesive surface of the adhesive carrier, whereinthe image carrier is not adapted to adhere to the substrate; wherein theimage carrier and the adhesive carrier are substantially coextensive insize.
 25. An adhesively mountable image graphic composite having areusable adhesive surface, comprising: (a) a flexible adhesive carrierhaving first and second major surfaces, each surface being substantiallycovered by an adhesive, the first adhesive surface engineered to bondthe adhesive carrier to a substrate and the second adhesive surfaceengineered to releasably secure an image carrier to the adhesivecarrier; (b) a flexible image carrier having first and second majorsurfaces, the first surface being imageable and the second surface beingin releasable contact with the releasably securing adhesive surface ofthe adhesive carrier; wherein the image carrier and the adhesive carrierare substantially coextensive in size.